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–+ servings
s'mores cake on parchment with large marshmallows, graham crackers, and crumbs

S'Mores Sheet Cake

4.67 from 3 votes
Prep Time: 25 minutes
Cook Time: 40 minutes
Additional Time 2 hours
Total Time: 3 hours 5 minutes
Author: Traci Crossland
A sweet cinnamon spiced cake, topped with a rich dark chocolate ganache, and finished with a homemade marshmallow fluff! This S'more Sheet Cake is the ultimate summertime baking treat.

Ingredients

Cinnamon Cake

  • 3 cups all purpose flour
  • 2 cups sugar
  • 1 Tablespoon baking powder
  • 1 teaspoon salt
  • 1 Tablespoon cinnamon
  • 3 large eggs
  • 1 cup milk
  • 1 teaspoon vanilla
  • ¾ cup unsalted butter, melted

Chocolate Ganache

  • 1 cup semisweet chocolate chips
  • 1 cup heavy cream

Marshmallow Topping

  • 3 ¾ teaspoons unflavored gelatin
  • ½ cup water, divided
  • ¾ cup sugar
  • ⅛ teaspoon salt
  • ½ cup corn syrup
  • 1 ½ teaspoons vanilla
US Customary - Metric

Instructions

Cinnamon Cake:

  • Heat oven to 350 degrees.
  • Spray an 8"x12" pan with baking spray. Set aside.
  • In a large bowl, whisk together flour, sugar, baking powder, salt, and cinnamon. Set aside.
  • Beat eggs, milk, and vanilla together.
  • Add wet ingredients to dry ingredients.
  • Whisk to combine.
  • Stir in melted butter.
  • Pour into prepared pan and bake for about 25 minutes, until cake tests done.

Ganache:

  • Place chocolate in a medium heatproof bowl. Set aside.
  • Heat cream on stove until it bubbles around the edges.
  • Pour over chocolate.
  • Let stand for 15 minutes.
  • Gently stir until completely combined and smooth.
  • Cover ganache with a piece of plastic wrap touching the chocolate to prevent skimming.
  • Place in refrigerator for 20-30 minutes, until it thickens.

Marshmallow Topping:

  • Combine gelatin and 1/4 cup water in the bowl of a stand mixer.
  • In a saucepan, combine remaining 1/4 cup water, sugar, salt, and corn syrup.
  • Cook over medium heat until sugar dissolves, stirring constantly.
  • Once sugar is dissolved, stop stirring.
  • Brush the sides of the pan down with a pastry brush dipped in warm water.
  • Allow to cook, without stirring, to 240 degrees on a candy thermometer.
  • Remove from heat.
  • With mixer running at low speed, slowly pour in syrup.
  • Continue beating for 5 - 10 minutes, until thickened but still soft.

How To Assemble:

  • Spread chocolate ganache on top of cooled cake.
  • Let sit for about 5 minutes, until firm.
  • Spread marshmallow topping on cake.
  • Using a kitchen torch, toast the marshmallow topping.

Notes

  • You can make the cake ahead of time but not the ganache or marshmallow fluff.
  • The marshmallow fluff will become harder to cut through as it cools. I fixed this by hitting it with a blow torch for a few seconds to warm it back up.
  • The ganache will melt slightly.
  • You can store this cake in the fridge.
  • Make sure not to over mix the cake batter!
  • A thermometer is needed to make the marshmallow fluff. You may burn it or create candy if you cook it anymore than the recommended temperature.
  • You can make the ganache over a bain-marie (double boiler).

Nutrition

Serving: 1sliceCalories: 314kcalCarbohydrates: 45gProtein: 4gFat: 13gSaturated Fat: 8gPolyunsaturated Fat: 1gMonounsaturated Fat: 4gTrans Fat: 1gCholesterol: 54mgSodium: 187mgPotassium: 93mgFiber: 1gSugar: 32gVitamin A: 378IUVitamin C: 1mgCalcium: 65mgIron: 1mg

Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.