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Rich Gooey Biscoff Crumb Bars

These Biscoff crumb bars are crazy rich but I can’t resist them! A thick and chewy cookie base topped with a layer of melty Biscoff spread, then roasted marshmallows and a crunchy crumb topping with a Biscoff drizzle…holy heaven!

We’ve been loving making campfire banana boats this summer and on a whim I made the most delicious Biscoff version. Immediately we all obsessed that it was the best banana boat ever but it didn’t stop there. By the next morning I’d barely slept as I kept dreaming of turning them into a dessert bar.

I debated sooooo much on every aspect of these bars but nothing as much as the base. Finally I decided on a snickerdoodle cookie base and I’m telling you, I am trying so hard to be humble but they are amazing. Even my family agrees, best dessert ever.

That slightly salty crumb topping is essential to balance this overly sweet bar and the marshmallow amount is totally up to you. I like a little less while my kids want more goo!

a photo of a rich and gooey biscoff crumb bar topped with melted marshmallows and crumb topping.

What is Biscoff?

Biscoff is a spread, similar in texture and consistency to peanut butter, made of ground up Biscoff cookies mixed with fat, flour and sugar.

What Flavor is Biscoff?

Biscoff spread and cookies have a warm caramel-y flavor with hints of brown sugar and cinnamon.

Where to Buy Biscoff?

You can find Biscoff at most grocery stores. I’ve seen it at Kroger stores, Walmart, Target, Trader Joe’s, Harmon’s, etc. You’ll find it either by the peanut butter and other nut butters or on the cookie aisle.

When you find it, grab a jar for this recipe and then grab another one and make our Biscoff stuff snickerdoodle cookies. You’ll thank me later!

a photo of a single Biscoff crumb bar sitting on a small dessert plate. it is topped with melted marshmallow, a crumb topping and a drizzle of Biscoff spread.

Ingredients for Biscoff Crumb Bars

Now that we have all those logistics out of the way and you know what you are looking for and where to look for it, here are the other ingredients you will need…

  • Butter: should be unsalted and softened so that is whips together with the sugars to be light and fluffy
  • Sugar: just regular white granulated sugar
  • Brown Sugar: adds richness and flavor
  • Vanilla: adds flavor
  • Eggs: one egg and an extra yolk will provide a perfect structure for the base of these dessert bars
  • Flour: just all-purpose flour
  • Salt: enhances all the flavors
  • Baking Powder: acts as a leavening agent and gives the bars their rise and fluffiness
  • Baking Soda: same purpose as the baking powder
  • Cream of Tartar: adds a little tang to the bars that is a snickerdoodle signature
  • Cornstarch: keeps the bars chewy but also fluffy
  • Biscoff: adds flavor, warmth, and the most delicious flavor
  • Mini Marshmallows: You will really want minis so that they melt perfectly. Regular size mallows just won’t melt and roast like we want.
a photo of several biscoff crumb bars sitting on a wire cooling rack.

Crumb Topping

  • Brown Sugar: adds sweetness, and richness of flavor
  • Sugar: adds sweetness
  • Flour: adds structure to the crumb topping
  • Cinnamon: adds flavor
  • Salt: enhances all the flavors
  • Butter: holds all the ingredients together into clumps and helps the topping get crunchy when it bakes

The measurements for each ingredient can be found in the recipe card at the end of this post. You can also save or print the recipe there.

a photo of a square baking dish full of biscoff dessert bars topped with creamy biscoff spread.

How to Make Biscoff Crumb Bars

This dessert bar recipe is made of layers of goodness. You start with a thick and chewy cookie base layer. The ingredients are simple and probably in your pantry and refrigerator already. It is rich and comforting.

After partially baking the base, we top it with a layer of warmed Biscoff spread and then a layer of mini marshmallows. The marshmallows gets roasted and melty and so delicious!

a photo of biscoff crumb bars topped with a layer of biscoff spread topped with mini marshmallows.

I’m getting a little ahead of myself. Before we stick the bars back into the oven, we top the marshmallows with a crumb topping. It adds a needed texture to the bars leaving crunchy nuggets in that sea of gooey roasted marshmallow. Drizzle a little more warm Biscoff spread all over the top for the final layer.

Ok, then into the oven it goes to finish baking and getting all delicious. I like to tent mine with a little foil to prevent it from getting too brown on top for the first part of this second bake.

a photo of a square baking dish full of biscoff crumb bars topped with melted marshmallows, a crumb topping and drizzled cookie butter.

Storing and Freezing Crumb Bars

Store any leftover Biscoff crumb bars in an airtight container just on the counter top at room temperature. They will keep for 4-5 days.

We have honestly never had any leftovers to freeze, so I can’t say for sure, but my guess is that they would not freeze well because of the marshmallow. You are forced to eat them all!

a photo of a biscoff crumb bar sitting on a piece of parchment paper on top of a wire cooling rack.

Take me to my happy place! You might think that that is Disneyland or the slopes at Deer Valley, but no! No, my happy place is sitting in my kitchen with Cade and the kiddos gobbling up these Biscoff crumb bars with a tall glass of milk!

Servings: 12 Bars

Prep Time: 15 minutes

Cook Time: 25 minutes

Total Time: 40 minutes


These Biscoff crumb bars have a thick and chewy base topped with a layer of melty Biscoff spread, then roasted marshmallows and a crunchy crumb topping with a Biscoff drizzle…holy heaven!

  • Mix the butter and sugars until smooth for 1 minute.

    1/2 Cup Butter, 1/2 Cup Sugar, 1/4 Cup Brown Sugar

  • Add the egg, yolk and vanilla and mix again until smooth, scraping down the sides of the bowl.

    1 Egg, 1 teaspoon Vanilla

  • Add all dry ingredients on low speed until well incorporated.

    1 1/2 Cup Flour, 3/4 teaspoon Salt, 1 teaspoon Baking Powder, 3/4 teaspoon Baking Soda, 1 1/2 teaspoon Cream of Tartar, 1 Tablespoon Cornstarch

  • Bake for 12 minutes at 350 in a parchment lined 8×8″ baking pan. meanwhile, melt the Biscoff for 20-30 seconds in the microwave.

    1 Cup Biscoff

  • Remove from the oven and gently place on the counter. Top with mallows and the crumb topping and drizzle with more Biscoff. Bake another 12-15 minutes. I tent mine with foil for the first half. Remove from oven to cool. Drizzle with a little biscoff and serve.

    2-3 Cups Mini Marshmallows

For the Topping

  • In a small bowl, using a fork or your fingers, combine the sugar, brown sugar, flour, cinnamon, salt and butter.

    3 Tablespoons Brown Sugar, 3 Tablespoons Sugar, 1/2 Cup Flour, 1 teaspoon Cinnamon, 1/4 teaspoon Salt, 4 Tablespoons Butter

Serving: 1BarCalories: 405kcalCarbohydrates: 53gProtein: 4gFat: 20gSaturated Fat: 9gPolyunsaturated Fat: 1gMonounsaturated Fat: 3gTrans Fat: 0.5gCholesterol: 44mgSodium: 368mgPotassium: 138mgFiber: 1gSugar: 30gVitamin A: 373IUVitamin C: 0.01mgCalcium: 32mgIron: 1mg

Author: Sweet Basil

Course: 100 Best Brownies and Bars Recipes, 500+ Best Dessert Recipes

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a photo of a biscoff crumb bar sitting on a torn piece of parchment paper so you can see the cross-section of a thick cookie base topped with melted marshmallows and crumb topping drizzled with cookie butter

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