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This overnight sausage, vegetable, and egg casserole can be frozen or made a day in advance for easy entertaining. Completely customizable and great for feeding a crowd!

Happy hump day, friends!
I’m bringing a new series to the blog: make ahead meals. I already have a few more in mind for this summer because, let’s face it, Matt and I have quite an adventure ahead of us, and while we sure do love to meal prep on Sundays… Life has gotten super cray, and make ahead meals have been and will likely continue to be a Godsend to us.
Our little dude arrived 5 days before his due date of June 19th, and in just 22 days, we have somehow managed to get absolutely nothing done. Except these red, white, and blue Rice Krispies Treats.
I must admit, though, it has been the most rewarding handful of days and we couldn’t be more excited about this new adventure we’ve begun together. Even if we are a little bleary-eyed and zombie-like and super stressed for the time being.
So what exactly do I mean by “make ahead,” you ask? I’m talking meals/dishes you can throw together in a snap and allow to sit in the fridge for a little while until you’re ready to eat them, but could also be finished sooner if needed.
WHAT’S THE ADVANTAGE OF A MAKE AHEAD MEAL?
Think: guests coming for brunch on Sunday morning that you’d like to actually spend some time with and not have your back on while you prepare food in the kitchen…
Hungry kids who wake up early on Christmas and want presents and something for their bellies all at one time (and likely at dark thirty in the morning when all you’d like to do is keep sleeping)…
OR a newborn baby who now runs your life and only allows you a little bit of time to do something at one time, forcing you to walk away from something at any given time and not being able to do start to finish in one sitting.
Yeah, we’re not pros yet, but we’ve learned some things.
So that’s what I’ve got for you today. Our favorite overnight breakfast casserole that comes together in about 15-20 minutes, sits in the fridge at least 2 hours but can last up to 1 whole day in there, and then bakes for 45 minutes right before you’re ready to eat it.
That’s only 1 hour of hands-on time that can spread out over 24 of them. See how this make ahead business is so handy?

A little disclaimer about this overnight breakfast casserole– it’s super customizable. I chose sausage and veggies for this particular dish, but if you’re a vegetarian, feel free to just replace the sausage with another veggie.
Or more of the ones that are already in there. And if you don’t want to use sausage, use another kind of meat. Whatever! This is your breakfast. You do you, friend.
HOW TO MAKE THIS BREAKFAST CASSEROLE EVEN QUICKER!
Another tip: start with fully cooked meat. This is especially helpful if you’re using something like leftover ground beef from the week or even something like a rotisserie chicken. But if you’re going the sausage route like I did, we like to buy fully cooked chicken sausage.
It’s one of our favorite meats to use during the week, and adding it to this breakfast casserole took the dish over the top!
Voila. Easy sausage breakfast casserole overnight in the fridge = super tasty sausage breakfast casserole in the morning in my mouth.
Don’t get me wrong, my quiches are some of my favorite meals to make, but this one has extra protein (meat) built right in. One stop shopping breakfast. More reasons to love this make ahead recipe.
Even when I start with fully cooked sausage, I like to brown it up just a bit in a skillet. Not totally necessary, but just something I like to do.
You’ll line your casserole dish with the meat, then throw your cooked veggie mix right on top. For this particular dish, I used garlic, spinach, bell peppers, and 1/2 an onion. Again, use whatever you like. Toss some mushrooms in there if you’re feeling fancy!
Lastly, your egg/milk/cheese mixture goes right on top of everything. This breakfast casserole features a whole 12 eggs. That’s some hearty breakfast!
If you’d prefer not to use a whole dozen, you could definitely get away with 10, or simply replace some whole eggs with egg whites instead. Like I said earlier: customizable. This recipe is not set completely in stone. It’s not cake! Although cake for breakfast… Hmm…
Ok, I’m getting distracted.
Once you’ve poured your egg mixture over all of the goodies, cover it tightly and allow it to sit in the refrigerator at least 2 hours. You could even freeze it at this point if you wanted to.
Although I really do recommend just chilling it and then baking it because I would not want to wait around to enjoy this sausagey, eggy, cheesy breakfast gloriousness!
ASSEMBLE, REFRIGERATE, BAKE!
Pssst… Check out those crispy edges!!

This dish was kid, parent, adult, and picky eater approved. We took the whole thing (minus 1 slice– sorry friends, that’s what happens when you invite a food blogger over for brunch!) to our friends with a 2 and 1/2 year old and he ate it right up.
Not without getting bell pepper chunks on his face (adorable), but most of it got in his belly which means I’m pretty sure he enjoyed it a lot.
Quick, easy, enjoyable hot, cold, or even room temperature… It’s so versatile and a great way to have a meal ready when you’re high on hunger and short on time. It’s also the most very perfect breakfast casserole for a crowd. Tuck it away for the holidays!
TURN IT INTO A FREEZER BREAKFAST CASSEROLE
If you’re looking for a breakfast casserole to stick in the freezer and eat at another time, this recipe is still for you!
To make ahead/freeze this casserole: you can freeze unbaked casserole up to 2 months. Cover very tightly with plastic wrap and foil. Thaw overnight in the refrigerator and continue with step 5 in the recipe (which is baking it).
I have a feeling this summer will feature a lot of this make ahead freezer breakfast casserole. Fresh produce + a newborn running our lives. Let’s make the best of the situation and use sleepiness and a new schedule as an excuse to eat all of the breakfast casseroles we can.

I’m definitely not mad about that.
Make Ahead Meal: Breakfast Casserole
Ingredients
- 12 ounces (340g) sausage casing removed*
- olive oil
- 2 cloves of garlic minced
- 3 cups (90g) fresh spinach
- 2 large bell peppers diced
- 1/2 medium yellow onion diced
- salt & pepper to taste
- 12 large eggs
- 1/2 cup (120g) milk any
- 1/2 cup (112g) shredded cheese any flavor
Instructions
- Spray a 7×11" or 9×13" casserole dish with non-stick spray. Set aside.
- In a large skillet over medium heat, brown the sausage. If you are using fully cooked sausage, you may skip this step. I like to brown my sausage just a little bit, even if it is already fully cooked. Spoon the browned sausage evenly into prepared casserole dish. Set aside.
- Add a little olive oil to the same large skillet (I use about 2 teaspoons since there is some grease left from the sausage). Sauté the garlic, spinach, peppers, and onion until vegetables are tender and spinach is wilted, about 6-7 minutes. Season with salt and pepper during the last minute or so. Add the cooked vegetable mixture to the sausage in the prepared casserole dish and roughly stir together to distribute mixture evenly. Set aside.
- In a medium size bowl, whisk together the eggs, milk, and 1/4 cup of the shredded cheese. Pour egg mixture evenly over sausage and vegetable mixture. Sprinkle with remaining 1/4 cup of shredded cheese and a little more salt and pepper. Cover casserole dish with plastic wrap or foil and refrigerate at least 2 hours or up to 1 day.
- When you are ready to bake the casserole: preheat the oven to 375ºF (191ºC) and bake for approximately 45 minutes or until edges start to brown. Allow to cool at least 15 minutes before serving. Store leftovers in the refrigerator up to 5 days. Reheat individual servings in the microwave as needed. Baked casserole may be frozen, up to 2 months. Thaw in refrigerator overnight and bake at 350ºF for about 20 minutes or until heated through.
- To make ahead/freeze this casserole: you can freeze unbaked casserole up to 2 months. Cover very tightly with plastic wrap and foil. Thaw overnight in the refrigerator and continue with step 5.
Leah @ Grain Changer says
Keep the make-ahead meals coming, Lynn! I’m noting every single one I come across these days, and this looks absolutely perfect for mom life!!!
Lynn says
Thanks, Leah! We loved this so much, and I think it’s about time I whip up another one. So easy and so necessary for this life, hahaha.
Amy says
Make ahead meals are awesome! I expect doubly awesome for new parents, but for busy people, lazy people, and people who just want some more time playing with their dog, they are awesome too! I love me a breakfast casserole, and I’ll be whipping up a veggie version in a heartbeat to get us through next week!
Lynn says
Hahaha, more time with the pup is a perfectly acceptable reason to want some make-ahead business!
Jess @ Sweetest Menu says
Well I think you’re amazing for getting the post up! And don’t worry about not getting anything else done, priority rules and you guys are going awesome! I love this breakfast casserole too. Totally my cup of tea! I look forward to trying!
Lynn says
Haha, why thanks, Jess!
Jenna says
Do you think I could make these in muffin tins and freeze them after baking?
Lynn says
Hi Jenna– absolutely! I would try baking them for 15-20 minutes first and then checking on doneness.
Meredith Runager says
looks great! Can’t wait to make! Just curious… after reasearching lots of breakfast casseroles, I found most call for some sort of bread/hashbrown ingredient to hold it together. However, yours does not. I assume it doesnt need it?! Thanks
Lynn says
That’s right, Meredith. No bread. I like to keep my recipes gluten free when I can to appeal to the masses, but you can certainly add bread! If you do, I suggest adding a couple more eggs. Enjoy!
Sabrina says
Hello! You think I can add chopped up bisquits at the bottom?
Lynn says
Hi Sabrina– you might be able to, but I worry about how soggy they may get. Typically, adding bread to a casserole like this is best done with stale, crusty bread.
Marilyn Rosin says
I was so excited to try this! I didn’t put it in the fridge to chill after I put it together and it didn’t come close to baking in 45 minutes. I checked and double checked that I put in the correct measurement of ingredients. Did I miss a critical step by not chilling the casserole?
Lynn says
Hi Marilyn– it shouldn’t make that much of a difference. How long did it wind up taking to bake?
Marilyn says
Thanks for your reply! I baked it an additional 20 minutes. It was delicious when it was finally done! I’ll try chilling it next time.
Lynn says
Glad to hear you enjoyed it! I’m not sure chilling really makes too much of a difference, it’s likely a difference of ovens. The chilling is more for flavor marriage and ability to make ahead. Either way, thanks for the feedback 🙂
Bonnie says
HI! When you bake it, do you keep it covered with tin foil or do you take the foil off? Thanks so much!
Lynn says
Hi Bonnie– I leave it uncovered, but if you prefer no browning on your eggs, you can cover it.
Sarah says
Hey Lynn – I just had to let you know that this is my “go-to” egg casserole recipe. It is always so delicious and gets lots of compliments! Thank you for such a great recipe!!
Lynn says
Thanks for letting me know, Sarah! Glad you and everyone else enjoy it 🙂
Laurie says
My husband & I made this for a friend that just had a baby. They LOVED it! Have you considered adding shredded potatos? Any thoughts about adding then for a frozen make ahead meal? Would love to hear your thoughts.
Lynn says
I’m so glad your friends loved the casserole! I had not considered that, but I’m sure it would work great. I might put it all in a bigger casserole dish, but I think it would work nicely!
Kelly says
I have made this before and it was easy and delicious! I want to make it again tomorrow for our Sunday school class but a few of my friends are lactose intolerant. Do you think soy milk will work?
Lynn says
Absolutely– or almond milk! We’ve used almond (UNSWEETENED, NOT FLAVORED) as well and it’s perfect!
eric Slayton says
Hi Lynn,
I stumbled upon this while preparing for my 31st Brunch which is tomorrow (celebrating my birthday a day early June 19) and I am ecstatic to try this out. I will let you know how it turns out. so excited!
Lynn says
Hey, Eric! Thanks for letting me know! I hope it turned out well and that you had a wonderful celebration. Happy birthday!
Jessika says
Has anyone actually frozen this uncooked, or cooked, and cooked/reheated successfully? I’m worrying the eggs won’t come out right after freezing…
Lynn says
We have! It works just fine 🙂
Jean says
I was looking for a do ahead brunch recipe and I found this. Looks good and sound good. Pray for me first time trying this.
Lynn says
How did it turn out, Jean?
Molly says
Do you think it would work to do this in the crock pot?
Lynn says
I don’t think so, Molly. The eggs would definitely get overcooked because I’m not sure of cooking time. But if you try it, let me know!
Ashley says
I’m thinking about making this for breakfast for our youth groups all nighter. How many people would you say a pan feeds?
Lynn says
Hi, Ashley– 8-10 servings as the recipe states!
Lauren Moyer says
At the end of the recipe you say it needs to be refrigerated for at least 2 hours. I’m thinking about my planning and time frame I will have available. If it doesn’t get refrigerated at all in between does that have a negative impact? Thanks!!! 🙂
Lynn says
It should not negatively affect the recipe, no.
Suzanne Meyers says
Lynn. After baking an egg milk snd bread casserole if it sat out all day is it still good
Lynn says
I wouldn’t chance that one!
Maria says
So, when you freeze it uncooked, does it have a tendency to stick to the pan?
When you thaw it, do you recommend thawing it in the refrigerator over night or on the counter?
Also, how does it work without the meat?
Lynn says
1) if you’ve pre-greased the pan, it should not stick any more than it would if you baked it right away.
2) see step 6 for freezing/thawing directions.
3) it would be fine without the meat. Same directions for baking.
Courtney says
Can I make the night before, refrigerate and then bake in the am?
Lynn says
Yes– the instructions are written to make up to 1 day in advance. See step 4.
Tammy says
I have made this at least a half dozen times over the past 4 months and have it in the fridge again right now.
This is the best, GF, flexible recipe! I’ve switched up the veggies numerous times and have done it vegetarian and loaded with sausage/bacon depending on the crowd. This is a great make-ahead answer to early morning gatherings or an easy breakfast for dinner.
Tomorrow’s version is vegetarian – packed with mushrooms, bell peppers, green chilis, and spinach.
Thank you for sharing this amazing recipe!
Lynn says
I love this so much, Tammy! I’m so glad you’ve been able to switch up the ingredients successfully and enjoy making your own versions. Thank you for sharing!
Lilly says
Could I bake it, freeze it in meal sized portions, and microwave when I’m ready to eat it?
Lynn says
That’s a great idea, Lilly!
Tabitha Helms says
Made this this morning for our extended family vacation (9 people to feed!) It was delicious and easy. I love how customizable the veggies are too. Will definitely be saving this one.
Lynn says
So glad you enjoyed it, Tabitha!
Alex says
Do you leave the cooked sausage whole when you line it on the bottom or cut it up into smaller pieces??
Lynn says
Cut it up!
Abby says
How long can leftovers last in the fridge? Thanks 🙂
Lynn says
5 days in the fridge!
Traci says
If using bacon, instead of sausage, should it go on the bottom still, or on top?
Lynn says
Hey, Traci– you can follow the same instructions. It will mix around just like it would if it were sausage. Enjoy!
Leah Shugart says
Any idea how this would be if I need to bake it and refrigerate it for a couple hours – thinking I could just heat it up a bit in the oven. I won’t be able to be home to bake this for the 45 minutes that it needs, but would like to have it for my sons First Communion brunch.
Lynn says
Sure thing, Leah! It should be perfectly fine. We’ve baked and reheated plenty of times. Enjoy!
Kathy says
Any recommendations if I wanted to throw in asparagus or broccoli? Should I par cook the asparagus before hand?
Lynn says
Hey, Kathy! I would throw them in where the instructions say the rest of the veggies go in!
Tara says
Hi there!
If I were to add shredded hash browns as the base, versus the meat, do you think I should brown them first before adding the veggies and egg? or will frozen potatoes work fine mixed in?
Thanks!
Lynn says
Yes, I would brown them first!
Sandy says
Just found this recipe, it’s exactly what I was looking for. I’m having first time out of town family as well as our immediate family for brunch, what is your favorite cheese to use?
Lynn says
Hi, Sandy! I really like cheddar for this one.
Suzanne says
Can this be cooked.. then frozen.. then reheated ?
Lynn says
Yes, thaw overnight in the fridge and then warm covered in the oven.
Brittney says
Would this be easily halved? I was thinking of that or to divide it into 2 smaller pans. It’s too much for my family of 4.
Lynn says
You can halve it if you’d like, but leftovers keep well if you can’t eat it all in one sitting.
Valerie Crane says
If you make this in individual ramekins, would the cook time be less?
Lynn says
Significantly, yes. I would try 8-10 minutes and see where that gets you.
Valerie Crane says
Thank you.
Michelle says
This has become my go to breakfast casserole. I make it every time we have company. Even my carb loving friends and family members love this, and they don’t miss the bread one bit. Thank you for sharing the recipe!
Lynn says
Thanks so much, Michelle! That means so much 🙂
Susie says
This sounds Soooooooo Delicious. I can’t wait to see how it turns out for me. I want to make it for my Family in Illinois on Christmas Day. Thank You for sharing with me. Will let you know how it goes. Take Care. Susie
Lynn says
Enjoy, Susie!
RaNae Ehrecke says
I want to bake this, then freeze, thaw and reheat. I’m thinking reheat at 350 for 1/2 hour? RaNae
Lynn says
See my notes in the recipe about freezing/making ahead! Reheating the whole dish after it’s been baked can dry it out. That’s why I like to freeze an unbaked dish. Hope this helps!
Christina says
Can I make this recipe in the morning (day before) and chill in refrigerator for 24hours instead of night before??
Lynn says
Yes. Enjoy!
Danielle Haluska says
This has become a staple in our home. I like to make it on Sundays and then eat it for a quick on the go breakfast throughout the week. Yum Yum Yum!
Lynn says
Love this! Thanks, D!