A super rich, not-too-sweet, dark chocolaty sheet cake that’s perfect for any party!

Prep: 30 mins
Cook: 25 mins
Additional: 1 hr
Total: 1 hr 55 mins
Servings: 24
Yield: 1 sheet cake

Ingredients

Cake:
1 ¾ cups all-purpose flour
1 cup dark cocoa powder (such as Hershey’s® Special Dark)
2 teaspoons baking soda
½ teaspoon salt
1 cup firmly packed dark brown sugar
½ cup white sugar
½ cup unsalted butter, softened
2 large eggs, at room temperature
2 teaspoons vanilla extract
1 cup strong brewed coffee, at room temperature
1 cup buttermilk, at room temperature

Frosting:
1 cup unsalted butter, softened
¾ cup dark cocoa powder (such as Hershey’s® Special Dark), sifted
1 teaspoon instant espresso powder
â…› teaspoon salt
2 teaspoons vanilla extract
3 cups powdered sugar, or to taste
7 tablespoons heavy whipping cream, or as needed

Directions

Step 1
Preheat the oven to 350 degrees F (175 degrees C). Grease a 10×15-inch rimmed baking sheet and line the bottom of the pan with parchment paper.

Step 2
Whisk flour, cocoa powder, baking soda, and salt together in a bowl until thoroughly combined. Set aside.

Step 3
Beat brown sugar, white sugar, and butter together in a large bowl with an electric mixer until light and fluffy. Beat in eggs one at a time, mixing well after each addition. Mix in vanilla extract. Add in 1/3 of the flour mixture, and mix until just combined. Add in 1/2 of the coffee and buttermilk, and mix until just combined. Continue alternating additions of the flour mixture with coffee and buttermilk, mixing just until combined. Pour batter into the prepared pan; smooth into an even layer. Tap pan firmly on the counter several times to remove air bubbles.

Step 4
Bake in the preheated oven until a toothpick inserted into the center of the cake comes out with a few moist crumbs, about 25 minutes. Do not overbake. Place cake on a wire rack and allow to cool completely.

Step 5
Meanwhile, make the frosting. Beat butter in a large bowl until completely smooth. Mix in cocoa powder, espresso powder, and salt until thoroughly combined. Mix in vanilla. Add in powdered sugar 1 cup at a time, mixing well after each addition. Pour in heavy cream and beat until frosting is light and fluffy, 2 to 3 minutes. If frosting is too thick, add more heavy cream.

Step 6
Spread frosting over the cooled cake.

Nutrition Facts

Per Serving:
286 calories; protein 3.3g; carbohydrates 39.2g; fat 14.6g; cholesterol 52.4mg; sodium 189.7mg.