S’mores Brownie with Marshmallow Fluff

This s’mores brownie is perfect for when you are craving s’mores but you don’t have a campfire. They are the prefect mash-up of two delightful treats. Kids will have a blast making these delightful treats.

I grew up on watching the movie The Sandlot and campfires. These greatly impacted my thoughts on s’mores and needless to say I love them. While this recipe does take a little bit of work then end results of this are well worth it!

In this recipe

This recipe comes in three parts but there are a lot of ingredients to this recipe. I promise you it is well worth the effort. Another cool thing about this recipe is that you can make the brownie in one pot. 

Yes, you read that correctly a pot. This is kind of the best thing ever if I do say so myself. Additional it is especially great for those working in small spaces. 

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By using cream of tartar the egg whites will become more stable and this will allow for a great marshmallow fluff. This is the key to getting the spongy soft texture that makes a toasted marshmallow distinctive. 

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Baking tips for working with egg whites:

      • Make sure the bowl and whisk/beater are clean. Any additional residue on the bowl or beaters will inhibit them from forming soft peaks.
      • Separate the egg whites one at a time into a separate bowl before adding them to the mixing bowl. That way if the egg yolk breaks into the white only one white is ruined. 
      • Pour the hot sugar syrup down the side of the bowl in a slow steady stream. This will prevent the sugar from cooking the egg whites.
S'mores Brownie with Marshmallow Fluff side view
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Coloring the marshmallow fluff is completely optional. However there is something that is very important and that is fire. In order to get that toasted flavor on the marshmallow fluffy a food blow torch or other heat source is needed. 

If a food torch isn’t an option then the broiler works perfectly well. Put the finished brownie with marshmallow fluff in the oven with the door open and watch to make sure the marshmallow doesn’t burn too much.

Baked S'mores Brownie with Marshmallow Fluff
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S'mores Brownie with Marshmallow Fluff ready to slice
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S'mores Brownie with Marshmallow Fluff

This gooey brownie is baked on a graham cracker crust and topped with fresh marshmallow fluff.
5 from 2 votes
Prep Time 40 minutes
Cook Time 1 hour 10 minutes
Total Time 1 hour 50 minutes
Course Dessert
Cuisine American
Servings 16 slices
Calories 449 kcal


  • Food processor
  • Stand mixer with whisk attachment
  • Food torch
  • Saucepan
  • 9" springform pan
  • Candy thermometer
  • Spatula
  • Piping bag with tips


Graham Cracker Crust

  • 6 tbsp butter unsalted, melted
  • 1 tbsp sugar
  • 1 tsp cinnamon
  • cups graham cracker crumbs 12 sheets


  • cup all-purpose flour
  • 1 cup cocoa powder unsweetened
  • ¾ tsp salt
  • 1 cup butter unsalted
  • 4 eggs
  • 1 cup sugar
  • 1 cup brown sugar
  • 1 tbsp instant espresso
  • 4 oz bittersweet chocolate chips
  • 2 tsp vanilla

Marshmallow Fluff

  • cup water
  • ¾ cup sugar
  • ¾ cup corn syrup light
  • 3 egg whites
  • ½ tsp cream of tartar


Making the graham cracker crust

  • Pre-heat the oven to 350°F or gas mark 4. Line the bottom of the spring form pan with parchment paper.
  • In a food processor add the graham cracker sheets and pulse until they are turned to crumbs.
  • Add the butter, sugar, and cinnamon and pulse until all ingredients and combined thoroughly.
  • Spread out the crumbs evenly on the bottom of the springform pan and bake for 8 min. Remove from the oven to cool.

Making the brownie

  • While the crust is baking in the oven, on medium heat melt the butter in a saucepan.
  • Once the butter has completely melted add espresso and cocoa powder. Mix until completely blended not letting the butter boil.
  • Remove from the heat and using a rubber spatula stir in the sugars until they are blended.
  • Add the eggs one at a time until blended. Be sure to not overmix.
  • Once all of the eggs are added pour in the flour, vanilla, and salt. Mix until combined, add the chocolate chips, and then pour into the graham cracker crust.
  • Reduce the heat to 325°F or gas mark 3.
  • Bake for 1 hour or until a toothpick or knife inserted in the center comes out clean. Remove from the oven and allow to cool on a rack.

Making the marshmallow fluff

  • In a saucepan add the sugar, water, and corn syrup. Stir the mixture until the sugar is evenly mixed.
  • Place on medium-high heat and bring to a boil. Once the sugar has dissolved do not stir otherwise crystals may form.
  • Cook until sugar syrup reached 240°F or 116C. Remove from the heat.
  • In a stand mixer combine the egg whites and cream of tartar and whisk until soft peaks form about 3-5 minutes.
  • Slowly pour the sugar syrup into the egg whites. Once all of the syrup has been poured into the egg whites increase the speed to high and whisk. The egg whites will collapse and then increase in volume. Continue to whisk until the egg whites become light and glossy.
  • Remove cooled brownie from the pan and spread or pipe the marshmallow fluff on top.


Serving: 1sliceCalories: 449kcalCarbohydrates: 66gProtein: 5gFat: 21gSaturated Fat: 13gPolyunsaturated Fat: 1gMonounsaturated Fat: 5gTrans Fat: 1gCholesterol: 83mgSodium: 348mgPotassium: 222mgFiber: 3gSugar: 53gVitamin A: 546IUVitamin C: 1mgCalcium: 62mgIron: 2mg
Nutrition Disclaimer*
Keyword Marshmallow Fluff, Smore, Toasted
Tried this recipe?Let us know how it was!
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