Recipes Desserts Cakes Sheet Cake Recipes Dark Chocolate Sheet Cake with Dark Chocolate Frosting 4.8 (21) 16 Reviews 6 Photos A super rich, not-too-sweet, dark chocolaty sheet cake that's perfect for any party! Submitted by Kim Updated on June 6, 2023 Tested by Allrecipes Test Kitchen Tested by Allrecipes Test Kitchen The Allrecipes Test Kitchen staff are a team of culinary pros who make and vet recipes using only equipment you'd find in a home kitchen. Staff credentials vary but include training at the Culinary Institute of America; kitchen stints in fine dining restaurants; and countless hours in the test kitchen itself. Meet the Allrecipes Test Kitchen Save Rate Print Share Close Add Photo 6 6 6 6 Prep Time: 30 mins Cook Time: 25 mins Additional Time: 1 hr Total Time: 1 hr 55 mins Servings: 24 Yield: 1 sheet cake Jump to Nutrition Facts Cook Mode (Keep screen awake) Ingredients 1x 2x 4x Oops! Something went wrong. Our team is working on it. Original recipe (1X) yields 24 servings 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 ⅛ teaspoon salt 2 teaspoons vanilla extract 3 cups powdered sugar, or to taste 7 tablespoons heavy whipping cream, or as needed Directions Gather all ingredients. Dotdash Meredith Food Studios 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. Whisk flour, cocoa powder, baking soda, and salt together in a bowl until thoroughly combined. Set aside. Dotdash Meredith Food Studios 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. Dotdash Meredith Food Studios Mix in vanilla extract. Dotdash Meredith Food Studios Add in 1/3 of the flour mixture, and mix until just combined. Dotdash Meredith Food Studios Add in 1/2 of the coffee and buttermilk, and mix until just combined. Dotdash Meredith Food Studios Continue alternating additions of the flour mixture with coffee and buttermilk, mixing just until combined. Dotdash Meredith Food Studios Pour batter into the prepared pan; smooth into an even layer. Tap pan firmly on the counter several times to remove air bubbles. Dotdash Meredith Food Studios 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. Dotdash Meredith Food Studios Meanwhile, make the frosting. Beat butter in a large bowl until completely smooth. Dotdash Meredith Food Studios Mix in cocoa powder, espresso powder, and salt until throughly combined. Mix in vanilla. Dotdash Meredith Food Studios Add in powdered sugar 1 cup at a time, mixing well after each addition. Dotdash Meredith Food Studios 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. Dotdash Meredith Food Studios Spread frosting over the cooled cake. Dotdash Meredith Food Studios I Made It Print Nutrition Facts (per serving) 286 Calories 15g Fat 39g Carbs 3g Protein Show Full Nutrition Label Hide Full Nutrition Label Nutrition Facts Servings Per Recipe 24 Calories 286 % Daily Value * Total Fat 15g 19% Saturated Fat 9g 45% Cholesterol 52mg 17% Sodium 190mg 8% Total Carbohydrate 39g 14% Dietary Fiber 2g 8% Total Sugars 29g Protein 3g 7% Vitamin C 0mg 0% Calcium 38mg 3% Iron 1mg 8% Potassium 153mg 3% * Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs. ** Nutrient information is not available for all ingredients. Amount is based on available nutrient data. (-) Information is not currently available for this nutrient. If you are following a medically restrictive diet, please consult your doctor or registered dietitian before preparing this recipe for personal consumption.