Description
A rich and moist Chocolate Mayonnaise Sheet Cake made with a unique mayonnaise-based batter and topped with a luscious chocolate frosting. This easy-to-make cake combines cocoa and instant coffee for a deep chocolate flavor, perfect for any occasion.
Ingredients
Scale
For the cake
- Butter, for greasing the pan
- 2 cups (242g) all-purpose flour
- 1 cup (120g) unsweetened Dutch processed cocoa powder
- 1 1/2 teaspoons baking powder
- 1 1/2 teaspoons baking soda
- 1/4 teaspoon salt
- 3/4 cup (177ml) hot water
- 2 tablespoons (30g) instant coffee powder or instant espresso powder
- 2 large eggs
- 1 cup (220g) sugar
- 1/2 cup (100g) brown sugar, lightly packed
- 1 cup (260g) mayonnaise
- 1 tablespoon vanilla extract
For the frosting
- 1/2 cup (80g) finely chopped semisweet or bittersweet chocolate
- 1/2 cup (113g) unsalted butter
- 2 tablespoons (30g) unsweetened Dutch processed cocoa powder
- 1 cup (130g) powdered sugar
- 1/2 cup heavy cream
Instructions
- Preheat and prepare pan: Preheat the oven to 350°F (180°C). Brush a 9×13-inch sheet pan with butter and set aside.
- Mix dry ingredients: In a medium bowl, stir together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt until evenly combined. Set aside.
- Dissolve coffee: In a glass measuring cup, add the instant coffee powder to the hot water. Stir until dissolved and set aside to cool slightly.
- Beat mayonnaise and sugars: In a large bowl, use an electric mixer to beat the mayonnaise, white sugar, and brown sugar until pale and creamy.
- Add eggs and vanilla: Add the eggs one at a time to the mayonnaise and sugar mixture, beating well after each addition. Scrape down the sides periodically to incorporate all ingredients. Add the vanilla extract and mix well.
- Combine wet and dry ingredients: Add the dry ingredients in three parts, alternating with the hot coffee in two parts. Beat after each addition until combined. The batter should be smooth, neither stiff nor runny.
- Bake the cake: Pour the batter into the prepared pan and bake for 30 minutes, or until a toothpick inserted into the center comes out with moist crumbs. Allow the cake to cool completely.
- Melt chocolate for frosting: Melt the chopped semisweet or bittersweet chocolate in the microwave using 20-second intervals, stirring between each, until smooth. Set aside to cool.
- Beat butter and sugar for frosting: In a large bowl, beat the unsalted butter until creamy and fluffy. Gradually add powdered sugar starting on low speed and then increasing, beating until combined and fluffy.
- Add cocoa powder: Add the cocoa powder to the frosting and beat well, scraping down the sides as needed for a smooth texture.
- Add cream and melted chocolate: Beat in the heavy cream and cooled melted chocolate until combined. Refrigerate the frosting for 10 minutes to set before frosting the cake.
- Frost the cake: Spread the frosting evenly over the cooled cake, creating swirls with a spatula or the back of a spoon.
- Serve and store: Slice and serve the cake. Cover the unfrosted cake in the tin with plastic wrap; store at room temperature for 1 day or refrigerate up to 7 days. After frosting, keep refrigerated for up to 3 days and allow the cake to come to room temperature before slicing.
Notes
- Ensure the melted chocolate for frosting is cooled slightly before adding to prevent the frosting from becoming grainy.
- You can substitute instant espresso powder for instant coffee powder without changing the flavor significantly.
- Use mayonnaise made with whole eggs for best flavor and texture.
- Letting the cake come to room temperature before serving improves the frosting’s texture and flavor.
- If you prefer, lightly grease the baking pan with butter or use parchment paper for easier removal.
- The combination of cocoa and coffee intensifies the chocolate flavor without adding bitterness.
Nutrition
- Serving Size: 1 slice
- Calories: 370 kcal
- Sugar: 35 g
- Sodium: 170 mg
- Fat: 22 g
- Saturated Fat: 8 g
- Unsaturated Fat: 10 g
- Trans Fat: 0.5 g
- Carbohydrates: 40 g
- Fiber: 3 g
- Protein: 4 g
- Cholesterol: 45 mg
