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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 taste amazing. Even my family agrees, best Biscoff dessert ever. Heck, I’ll even go so far as to say, best dessert ever! Yes, I said it!
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!
What is Biscoff Cookie Butter?
Biscoff is a spread, similar in texture and consistency to peanut butter, made of ground up Biscoff cookies (also known as speculoos cookies) mixed with fat, flour and sugar. Lotus biscoff cookies is the most common brand I’ve seen.
What Flavor is Biscoff?
Biscoff spread and cookies have a warm caramel-y flavor with hints of brown sugar and cinnamon. You can’t beat the biscoff flavor! We have all kinds of biscoff recipes…biscoff cookies, biscoff cheesecake, biscoff ice cream, and biscoff banana bread!
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!
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 Extract: 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.
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.
How to Make Biscoff Crumb Bars
This dessert bar recipe is made of layers of goodness. I like to start by making the crumb topping just so it’s ready to go when I need it. Then move to the thick and chewy cookie base layer that acts as a crust for bars. The ingredients for the cookie base mixture 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!
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.
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 2-3 days. Store them in the fridge and they will keep for up to a week.
We have honestly never had any leftovers to freeze, so I can’t say for sure how they would do in the freezer, but my guess is that they would not freeze well because of the marshmallow. You are forced to eat them all!
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! Our favorite sweet treat!
More Bar Dessert Recipes:
- Raspberry Lemon Tart Bars
- Mom’s Famous Caramel Brownies
- Brown Butter Dulce de Leche Rice Krispie Treats
- Cinnamon Roll Cheesecake Bars
- Fruity Pebbles Rice Krispie Treats
- Blackberry Cheesecake Brownies
- Classic Lemon Bars
- Twix Caramelita
Watch How to Make Biscoff Bars
Biscoff Crumb Bars
Ingredients
Crumb Topping
- 3 Tablespoons Sugar
- 3 Tablespoons Brown Sugar
- 1/2 Cup Flour
- 1 teaspoon Cinnamon
- 1/4 teaspoon Salt
- 4 Tablespoons Butter, softened
Cookie Base
- 1/2 Cup Butter, unsalted, softened
- 1/2 Cup Sugar
- 1/4 Cup Brown Sugar
- 1 teaspoon Vanilla
- 1 Egg, plus 1 egg yolk
- 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
- 1 Cup Biscoff
- 2-3 Cups Mini Marshmallows
Instructions
For the Topping
- In a small bowl, using a fork or your fingers, combine the sugar, brown sugar, flour, cinnamon, salt and butter. Set aside for later.3 Tablespoons Brown Sugar, 3 Tablespoons Sugar, 1/2 Cup Flour, 1 teaspoon Cinnamon, 1/4 teaspoon Salt, 4 Tablespoons Butter
For the Cookie Base
- Preheat the oven to 350 degrees F and line an 8×8" baking pan with parchment paper.
- 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
- Press the cookie base into the prepared baking dish and bake for 12 minutes. Meanwhile, melt the Biscoff for 20-30 seconds in the microwave.1 Cup Biscoff
- Remove the partially baked cookie base from the oven and gently place on the counter. Top with about a half cup of Biscoff you warmed up in the microwave and spread around to cover the base. Then sprinkle with the mallows followed by the crumb topping and drizzle with about 1/4 cup of Biscoff.2-3 Cups Mini Marshmallows
- Bake another 12-15 minutes. I tent mine with foil for the first half. Remove from oven to cool. Drizzle with a little the remaining Biscoff and serve.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Hey have not tried these yet but will just wanted to know if I double this recipe will I use a 9 by 13 pan
Hi Judith! You can double it to a 9×13 pan but it will be a little thicker. It may need another couple minutes of bake time. You could also 1.5 the recipe and have them be a little thinner. Enjoy!
We tried these and LOVED them. My daughter wants it for her birthday “cake”. Do you think it would work double the recipe and to bake it in a cheesecake pan so I could take off the sides and put candles in it?
Thank you so much Marianne! Yes, that should work great! Happy birthday to your daughter!
Mine just turned into a buttery sunken mess. I followed the directions and measurements to the T! Not sure what happened. Tastes great! But the cookie part at the bottom definitely did not bake up like a cookie!
Hmmmm…I’m not sure what could have gone wrong. You did the partial bake of the cookie bottom first? And did you use the correct size pan? I’m so sorry for the disappointment!
Would marshmallow cream or fluff work in lieu of mini marshmallows?
Hi Dane Ann! This is a great question! I haven’t ever tried it, so I can’t say for sure. It would be worth a shot!
Ditto to Connie K.’s question. We have a Christmas cooking baking extravaganza coming up and I will be making this recipe….Thanks!
Hey Sheri! I just answered Connie. So sorry for the confusion! Enjoy!
Thank you so much!
Hello, I just wanted to clarify a recipe step, I am assuming once you take the Biscoff out of the microwave, you pour it over the cookie base then add the marshmallows and crumb topping and topped with more Biskoff? Thanks!
Hi Connie! Thank you for bringing this to my attention! The instructions were quite vague. I’ve update the recipe card but basically you cover the cookie base with Biscoff, then the marshmallow, then the crumb topping, then a little more Biscoff. Then after it bakes the second time you top it with a little more Biscoff! I hope you enjoy it!
I was worried this was going to be way too sweet, but it wasn’t. Just amazingly delicious!!! Thank you!
Thank you so much Kelley! I was actually worried about the same thing when I first created this recipe, but it totally works and is balanced. They are rich, but not overly sweet!
This was dangerously delicious! I had to give away pieces to keep from eating the entire thing!
I totally have to do the same thing or I will eat the whole pan!