Dark Chocolate Sheet Cake with Dark Chocolate Frosting

A super rich, not-too-sweet, dark chocolaty sheet cake with a dark chocolate frosting that's perfect for any party!

• Preparation Time: 30 mins
• Cooking Time: 25 mins
• Total Time: 55 mins
• Calories: 286 Calories

Ingredients

• 2 teaspoons vanilla extract
• 2 teaspoons baking soda
• 1 cup unsalted butter, softened
• 1 cup buttermilk, at room temperature
• 2 large eggs, at room temperature
• 1 teaspoon instant espresso powder
• 1 cup firmly packed dark brown sugar
• 1 cup strong brewed coffee, at room temperature
• 3 cups powdered sugar, or to taste
• 7 tablespoons heavy whipping cream, or as needed
• 0.5 teaspoon salt
• 0.5 cup white sugar
• 0.5 cup unsalted butter, softened
• 0.125 teaspoon salt
• 1.75 cups all-purpose flour
• 1 cup dark cocoa powder (such as Hershey's® Special Dark)
• 0.75 cup dark cocoa powder (such as Hershey's® Special Dark), sifted

Recipe Instructions

Step 1

Preheat the oven to 350 degrees F (175 degrees C). Grease a 10x15-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

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 4

Spread frosting over the cooled cake.

Step 5

Gather all ingredients.

Step 6

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.

Step 7

Mix in vanilla extract.

Step 8

Add in 1/3 of the flour mixture, and mix until just combined.

Step 9

Add in 1/2 of the coffee and buttermilk, and mix until just combined.

Step 10

Continue alternating additions of the flour mixture with coffee and buttermilk, mixing just until combined.

Step 11

Pour batter into the prepared pan; smooth into an even layer. Tap pan firmly on the counter several times to remove air bubbles.

Step 12

Meanwhile, make the frosting. Beat butter in a large bowl until completely smooth.

Step 13

Mix in cocoa powder, espresso powder, and salt until throughly combined. Mix in vanilla.

Step 14

Add in powdered sugar 1 cup at a time, mixing well after each addition.

Step 15

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.