2Tablespoons(30mL) olive oilplus more for the frying pan
1 and ½teaspoonssalt
1large onionroughly chopped
228-ounce cans(1588g) crushed tomatoes
In a large bowl, lightly beat the egg. Add the ground turkey, flaxseed, Parmesan cheese, olive oil, garlic, oregano, basil, salt, and pepper. Stir with a large spatula until completely combined.
Roll meat mixture into balls and place on a large plate or platter until you are ready to cook them. I like to use a cookie scoop (for medium size meatballs) or ice cream scoop (for larger meatballs). My meatballs are usually around 1oz in weight/size. Set aside.
Place the chopped onion in the bottom of a slow cooker4, then top with one can of the crushed tomatoes.
Heat a large skillet with olive oil over medium heat. Lightly brown the meatballs (about 8 at a time), about 1-2 minutes each side. Place each batch of browned meatballs into the slow cooker until all meatballs are browned. Cover meatballs with second can of crushed tomatoes.
Cover the meatballs and cook4 on low for 6-7 hours or high for 4-5 hours. Leftovers will stay fresh in the refrigerator, covered, up to 1 week.
Make ahead: prepare meatballs through the browning step, then cover and refrigerate up to 1 day or freeze up to 2 months. Add to slow cooker cold or frozen and cook as directed. Alternatively, fully prepare up to 1 day in advance, refrigerate, then reheat in the slow cooker on low for 1 hour. Cooked meatballs can be frozen in sauce up to 2 months. Defrost in refrigerator before reheating.
Meat: use any ground meat here.
Ground flaxseed: if you don't need or want these to be gluten-free, replace with the same amount of breadcrumbs.
Make them dairy-free: replace Parmesan cheese with ⅓ cup gluten free breadcrumbs, ⅓ cup vegan cheese, or⅓ cup additional ground flaxseed. I like to change up the texture and use breadcrumbs.
No slow cooker? Use your stove top: follow the same preparation instructions, and simmer over medium-low heat until sauce thickens and meatballs are fully cooked, about 35 minutes.
Test for doneness: I check a few meatballs with a meat thermometer to ensure food safety. You're looking for 165°F (74°C) for poultry.