Biscoff Butterscotch Marshmallow Sandwich Cookies
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Chewy Biscoff-infused cookies and a dreamy butterscotch marshmallow buttercream come together in a sandwich cookie that’s sweet, tender, and guaranteed to disappear fast.
Two Winning Recipes, One Show-Stopping Cookie
I love when a flavor idea I have turns out to be as successful in practice as it is in my head, and what an incredible bonus when I combine two recipes into one and that combo recipe is a winner, too. This must-have, grab-the-ingredients-immediately, better-start-preheating-the-oven sandwich cookie is the brainchild of two previously successful Fresh April Flours cookies: Biscoff cookies with butterscotch frosting and gingerbread sandwich cookies.
The first one? A flavor combo inspired by Gideon’s Bakehouse, a gourmet cookie and cake shop in Disney Springs, made its way into my frosted cookie series and took the whole series by storm. After one taste of that cookie, I decided Biscoff and butterscotch were the underdog of the flavor pairing world and it would not be the last time that it showed up on my website.
The second one was my first ever adventure into the sandwich cookie world, and it became the most popular cookie recipe in my 2024 edition of 12 Days of Cookies. I had taste testers say it was the best cookie they’ve ever had, and I read similar sentiments in the comments that rolled in all Christmas season long.
It only seemed right to add another sandwich cookie to my recipe collection, and when picking a flavor combo, there was no question that Biscoff + butterscotch was going to be the ticket. I took notes from the gingerbread sandwich run and turned the classic butterscotch frosting into a fluffy marshmallow version, and I have to say… This Biscoff sandwich cookie may give the gingerbread one a run for its money!
HERE’S WHAT YOU’LL NEED
Here’s a visual of the ingredients you’ll need to make the cookies and the frosting. Be sure you’re scrolling down to the recipe card to find exact amounts as well as the preparations for each of the ingredients.
And yes, you can use off-brand cookie butter and cookie butter cookies. Speculoos is the Trader Joe’s brand, and I even heard from a little bird that there are gluten free cookie butter cookies and spreads out there so our gluten free folks aren’t totally left out. We all win with this one!
OVERVIEW: HOW TO MAKE BISCOFF SANDWICH COOKIES
Make the cookie dough: this is a super simple cookie dough that doesn’t need any chilling time, though it does need some resting time. Be sure your butter is at room temperature and no warmer, as these cookies can spread too much if your butter is too warm.
Bake the cookies: be sure to pull these cookies from the oven as soon as the edges look set and the tops lose their shine. If they bake too long, they’ll firm up more than ideal for sandwiching. But fear not! Once they’re filled, the frosting will help soften them back up. It may just take a day for them to settle into that perfect sandwich cookie texture.
Reshape while warm: I like to do this with all of my cookies, but it’s extra important for sandwich cookies since you want them as uniform as possible. While the cookies are still piping hot, use a 4″ round cookie cutter– or even the rim of a glass– to contain the edges.
Cool completely before sandwiching: never fill even slightly warm cookies– the frosting will melt into a mess! In a hurry? Give them a quick chill in the fridge or even outside if it’s cold. They’ll usually cool on their own fast enough, so take the time to whip up the frosting while you wait.
Make the frosting: this butterscotch marshmallow frosting is super simple but requires a little more elbow grease than traditional buttercream frosting. Since you’re melting butterscotch chips, you’ll need to wait until that mixture cools a bit before you use it. Just be sure it doesn’t harden! That makes for a terrible start to frosting (and ask me how I know…). If it becomes too firm, give it a gentle re-melt before combining it with the butter and fluff.
Assemble the sandwiches: begin by matching cookies of similar size, bottom sides facing each other. Pipe or spread the frosting onto one cookie, leaving a small border around the edges. Then, place the second cookie on top and gently press to create the perfect sandwich.
HELP: MY COOKIES SPREAD!
All is well in the oven, my baker! I have tested these Biscoff cookies many times, and occasionally it appears that even the moisture content of the batch of Biscoff cookies I use can affect the way the cookies behave in the oven.
Here’s my best advice: be sure you’re using exactly 10 cookies (standard size, not XL), weighing your flour, using room temperature butter (and no warmer!), and giving the cookie dough balls a quick roll with your hands before baking.
Reshape after the oven: this is also another way to contain cookies that may have spread a little more than is preferred. Here is a visual from reshaping my gingerbread sandwich cookies. This will also help keep the cookies a uniform size, perfect for pairing as sandwiches!
CAN I USE A DIFFERENT FROSTING?
You can absolutely use any frosting to fill these cookies that you prefer. Fill your Biscoff sandwich cookies with cream cheese filling, traditional vanilla buttercream, or add some Biscoff spread to either of those aforementioned frostings. There is no wrong way to fill these cookies, but gosh, that butterscotch flavor is such a perfect pairing!
Biscoff Butterscotch Marshmallow Sandwich Cookies
Ingredients
BISCOFF COOKIES
- 1 cup + 2 Tablespoons (135g) all-purpose flour be sure to measure properly
- 10 Biscoff cookies1 crushed into a fine crumb, about ½ cup
- 1 teaspoon cornstarch
- ½ teaspoon baking soda
- ¼ teaspoon baking powder
- ½ teaspoon salt
- ½ cup (113g) unsalted butter softened to room temperature
- ¾ cup (150g) firmly packed light brown sugar
- 1 large egg at room temperature
- 1 teaspoon vanilla extract
- ½ cup (120g) Biscoff cookie butter1
BUTTERSCOTCH MARSHMALLOW FROSTING
- 4 ounces (113g) butterscotch chips
- ½ cup (113g) unsalted butter softened to room temperature
- 2 ounces (57g) marshmallow fluff
- 1 to 2 Tablespoons (15-30mL) room temperature water2
- 1 and ¾ cups (210g) powdered sugar
- ¼ teaspoon salt
Instructions
BISCOFF COOKIES
- Preheat the oven to 350°F (177ºC). Line a large baking sheet with parchment paper or a silicone baking mat. Set aside.
- In a medium size bowl, combine the flour, crushed Biscoff cookies, cornstarch, baking soda, baking powder, and salt. Whisk together until everything is combined, then set aside.1 cup + 2 Tablespoons (135g) all-purpose flour, 10 Biscoff cookies1, 1 teaspoon cornstarch, ½ teaspoon baking soda, ¼ teaspoon baking powder, ½ teaspoon salt
- In a large bowl with a handheld mixer or the bowl of a stand mixer fitted with the paddle attachment, cream together the the butter and brown sugar on medium-high speed until light and fluffy, about 2-3 minutes. Add the egg and vanilla extract and beat again until everything is combined.½ cup (113g) unsalted butter, ¾ cup (150g) firmly packed light brown sugar, 1 large egg, 1 teaspoon vanilla extract
- Add the cookie butter and mix until combined. Turn off the mixer, scrape down the sides and bottom of the bowl, then beat on low until everything is incorporated.½ cup (120g) Biscoff cookie butter1
- Turn the mixer speed to medium, then slowly add the flour and blend until no flour pockets remain. Cover the cookie dough and allow it to rest for 10 minutes.
- Using a cookie scoop (I use this #50 cookie scoop for all of my standard size cookies), drop rounded balls of dough onto the prepared baking sheet. Use your hands to roll them into a smooth ball. The dough will be soft but should not be sticky.
- Bake the cookies for 8-10 minutes just until edges are just set. The centers will look underdone. Working quickly but carefully, use a large round cookie cutter or the rim of a glass or mug to reshape hot cookies. This will tuck in any edges that got thin and make the cookies uniform in size. Allow to rest on the baking sheet for 10 minutes before transferring to a wire cooling rack to cool completely before making sandwiches.
BUTTERSCOTCH MARSHMALLOW FROSTING
- In a small saucepan over medium heat or in a microwave safe bowl in the microwave, melt the butterscotch chips until smooth. Remove from heat and allow to cool for 10 minutes4 ounces (113g) butterscotch chips
- In a medium size bowl with a handheld mixer or the bowl of a stand mixer fitted with the paddle attachment, combine the cooled butterscotch mixture, butter, and marshmallow fluff, and beat on medium-high speed until smooth, about 2-3 minutes. Add water, starting with just 1 Tablespoon, and blend on medium speed until combined.½ cup (113g) unsalted butter, 2 ounces (57g) marshmallow fluff, 1 to 2 Tablespoons (15-30mL) room temperature water2
- Turn the mixer down to low and slowly add the powdered sugar. Increase mixer speed to medium and beat until completely combined, scraping down sides as needed. Add the salt, taste, and add more salt if needed. Turn off the mixer and use a spatula to stir the buttercream by hand to remove air bubbles and make it smooth and creamy. This usually takes about 3-5 minutes.1 and ¾ cups (210g) powdered sugar, ¼ teaspoon salt
ASSEMBLE THE SANDWICH COOKIES
- When you are ready to assemble the sandwiches, pair the cookies, bottom to bottom, with like-sized/shaped cookies as best as possible.
- Working with the bottom cookie of one pair at a time, add the frosting to a piping bag or use an offset spatula to spread frosting onto the bottom of the cookie. Leave about ½" border so you can "squish" the cookies together.
- Take the top cookie and press the bottom of the cookie onto the fresh frosting to make a sandwich. Press the cookies together gently so the frosting moves to the edges. Cookies can be served immediately, but in my opinion, they get better as they sit! Store filled gingerbread cookies covered tightly at room temperature for up to 5 days. Cookies freeze well, up to 3 months. Unbaked cookie dough balls freeze well, up to 3 months. Do not roll in sugar, allow to thaw in the refrigerator, then roll in sugar and bake as directed.
- Make ahead: you can make the cookies and/or frosting up to 2 days in advance. Store at room temperature covered tightly, then assemble when you are ready.
Video
Notes
- Biscoff brand: you can use any other brand of cookie butter that you prefer or can find. The Trader Joe’s equivalent is Speculoos cookies and cookie butter spread.
- Room temperature water: it is imperative your water is at room temperature so it does not disrupt the texture of the melted butterscotch chips. You could also use cream or milk, but you must make sure it is not completely cold.
Nutrition Disclosure
All nutritional values are approximate and provided to the reader as a courtesy. Changing ingredients and/or quantities will alter the estimated nutritional calculations.