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functional image chocolate marshmallow sheet cake top down marshmallow meringue and an offset spatula on gray marble
Heather Wolf

Chocolate Marshmallow Cake

5 from 3 votes
Chocolate Marshmallow Cake is proof that love comes in all shapes and sizes: including a rectangular baking pan. Easy to make and even easier to transport, this chocolaty sheet cake is topped with fluffy marshmallow frosting.
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Prep Time 15 minutes
Cook Time 35 minutes
Marshmallow Frosting 25 minutes
Total Time 1 hour 15 minutes
Servings: 12
Course: Cakes and Cupcakes
Cuisine: American
Ingredients Equipment Method

Ingredients
  

Chocolate Cake
  • 2 cups all-purpose flour unbleached
  • 2 cups granulated sugar
  • 3/4 cup unsweetened cocoa powder
  • 2 tsp baking soda
  • 1 tsp baking powder
  • 1 tsp sea salt
  • 1 tsp espresso powder
  • 1/2 cup olive oil extra virgin
  • 2 large eggs room temperature
  • 2 tsp vanilla extract pure
  • 1 cup buttermilk room temperature
  • 1 cup hot coffee
Marshmallow Frosting
  • 6 large egg whites room temperature
  • 1 1/2 cups granulated sugar
  • 3/4 tsp cream of tartar
  • 1 1/2 tsp vanilla extract pure
  • 1/8 tsp sea salt fine

Equipment

  • Electric mixer

Method
 

Chocolate Cake
  1. Preheat oven to 350 degrees. Coat a 9 x 13 metal baking pan with nonstick baking spray. Set aside.
  2. In a large mixing bowl, sift together dry ingredients: flour, sugar, cocoa powder, baking soda. baking powder, salt and espresso powder. Set aside.
  3. In a separate bowl, whisk together oil, eggs and vanilla.
  4. Add buttermilk then whisk until combined.
  5. Add the dry ingredients to the bowl of wet ingredients and stir with a spoon until just combined. Take care to avoid overmixing.
  6. Carefully pour hot coffee into the batter and stir until evenly incorporated.
    Note: batter will be thin.
  7. Pour batter into prepared baking pan and bake for 35 minutes or until a tester inserted into the center of the cake comes out clean.
  8. Place baking pan on a wire rack to cool completely, approximately 2 hours, before topping with marshmallow frosting. 
Marshmallow Frosting
  1. Using a double boiler, bring an inch or two of water to a simmer. Continuously whisk egg whites and sugar over heat until sugar has completely dissolved, approximately 7 minutes.
  2. Immediately transfer marshmallow meringue to a clean mixing bowl and beat with an electric mixer until soft peaks form, approximately 5 minutes.
  3. Add cream of tarter, vanilla and salt and continue beating until stiff peaks form, approximately 10 to 12 minutes.
  4. Spread frosting onto cooled cake then slice and serve.
  5. Note: Frosting will begin to wilt if let at room temperature. To prevent wilting, cover and chill cake in the refrigerator up to 2 days.