Marshmallow Cake

Ingredients

FOR THE CAKE

• Cooking spray
• 2 c. all-purpose flour
• 3/4 c. unsweetened cocoa powder 
• 1 tsp. baking soda
• 1 tsp. kosher salt
• 1 c. hot coffee
• 1 c. granulated sugar
• 1/2 c. packed brown sugar
• 3/4 c. vegetable oil
• 1/2 c. sour cream, room temperature

FOR MARSHMALLOW FROSTING

• 3 large egg whites, room temperature
• 1/4 tsp. cream of tartar
• 1 1/2 c. granulated sugar
• 3/4 c. water
• 1 tsp. pure vanilla extract 

Directions

1. Make cake: Preheat oven to 350°. Line two 8” cake pans with parchment and grease with cooking spray. In a large bowl, whisk together flour, cocoa powder, baking soda, and salt. 
2. In another large bowl, whisk hot coffee and sugar together. Add oil and sour cream and whisk to combine. Pour into dry ingredients and whisk until just combined. 
3. Divide batter between prepared pans and bake until a toothpick inserted in middle comes out clean, 25 to 30 minutes. Let cool 15 minutes, then invert onto a wire cooling rack and let cool completely. 
4. Make frosting: Place egg whites and cream of tartar into the bowl of a stand mixer or heat safe mixing bowl. In a small pot over medium heat combine sugar and water and bring to a simmer. Without stirring, watch pot carefully until mixture reaches 230° to 235°, but keep mixture over heat. Use a wet pastry brush to wipe sides of pot as sugar crystals form. 
5. As soon as sugar mixture reaches 230° begin to whip egg whites using the whisk attachment or hand mixer. Continue beating until egg whites are frothy and sugar mixture reaches 240°. This should happen around the same time. 
6. As soon as mixture reaches 240° very slowly stream mixture into egg whites while beating on medium-high speed. Then pour in vanilla. Continue beating until egg whites double in volume and mixture is smooth, glossy, and stiff peaks form.
7. Assemble cake: Trim tops of cake using a serrated knife to make a smooth, flat top, as needed. Place one layer of cake on a serving platter and top with a heaping amount of frosting. Use an offset spatula to smooth into an even surface. Top with second layer and frost tops and sides. If desired, use a kitchen torch to toast meringue.