This Heaven and Hell Sheet Cake boasts a rich, moist, and intensely chocolatey cake base, perfectly complemented by a light and airy, marshmallow-like frosting. The contrast in textures and the deep chocolate flavor make this cake a truly heavenly experience.

Heaven and Hell Sheet Cake

Ingredients:

For the Cake:

For the frosting:

To make the cake:

1. Preheat oven and prepare pan: Preheat oven to 350°F (175°C) and grease a 9×13 inch baking pan with baking spray. Set aside.
2. Whisk dry ingredients: In a medium bowl, whisk together the all-purpose flour, baking soda, and fine salt. Set aside.
3. Combine wet ingredients (coffee mixture): In another bowl, combine the hot coffee, cocoa powder, and finely chopped dark chocolate. Whisk until the chocolate is completely dissolved and the mixture is smooth. Let the mixture cool slightly. Once slightly cooled down, whisk in the room temperature buttermilk. Set aside.
4. Cream butter and sugar: In a separate large bowl, beat the room temperature vegetable oil, room temperature unsalted butter, and packed light brown sugar together until they are completely combined and smooth.
5. Add eggs: Add the large eggs one at a time to the butter and sugar mixture, beating well after each addition until fully incorporated.
6. Combine wet and dry ingredients: Gradually add the dry ingredients to the wet ingredients in three additions, alternating with the wet coffee-cocoa mixture in two additions. Begin and end with the dry ingredients. After each addition, mix until just combined. Use a rubber spatula to scrape down the sides and bottom of the bowl to ensure everything is properly incorporated. Be careful not to overmix.
7. Bake the cake: Pour the batter into the prepared 9×13 inch baking pan and spread it evenly. Bake in the preheated oven for about 25 to 30 minutes, or until a toothpick inserted into the center of the cake comes out mostly clean with a few moist crumbs attached.
8. Cool completely: Remove the baked cake from the oven and let it cool completely in the pan on a wire rack before frosting.

To make the frosting:

1. Prepare water bath: Fill a small saucepan with about an inch or two of water and set it over medium-low heat. Bring the water to a gentle simmer, then reduce the heat to low to maintain a simmer.
2. Combine frosting base: In the bowl of a stand mixer (or a heatproof bowl that can sit over the saucepan without touching the water), combine the sugar, corn syrup, and egg whites.
3. Heat and whisk: Place the mixing bowl over the pot of simmering water. Constantly whisk the egg white mixture for 7 minutes. The mixture will gradually become opaque, smooth, and slightly thickened.
4. Whip to marshmallow consistency: Carefully transfer the heated egg white mixture to the bowl of a stand mixer fitted with the whisk attachment. Whip on high speed until the mixture doubles in volume and forms stiff, glossy peaks, resembling a fluffy marshmallow consistency. This will take several minutes.
5. Add vanilla: Once stiff peaks have formed, add the vanilla extract and whip for another minute to combine.
6. Frost and serve: Once the cake is completely cooled, spread the prepared frosting evenly over the top. Slice and serve. Enjoy this delightful Heaven and Hell Sheet Cake!