Description
This Chocolate Mayonnaise Sheet Cake is a rich, moist, and tender cake that uses mayonnaise to create a wonderfully soft texture without the need for oil or butter in the batter. Featuring a deep chocolate flavor enhanced by coffee and a luscious chocolate frosting, it's a perfect dessert 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: Preheat the oven to 350°F (180°C). Brush a 9x13-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 this mixture aside.
- Dissolve Coffee: In a glass measuring cup, mix the instant coffee powder with the hot water until fully dissolved. Set aside to cool slightly.
- Beat Mayonnaise and Sugars: In a large mixing bowl, using an electric beater, beat the mayonnaise with the white and brown sugars until pale and creamy.
- Add Eggs and Vanilla: Add the eggs one at a time to the mayonnaise mixture, beating well after each addition. Scrape down the sides of the bowl periodically. Then add the vanilla extract and beat to combine.
- Combine Wet and Dry Ingredients: Divide the dry ingredients into thirds. Add the first third of dry ingredients along with half of the coffee mixture to the wet mixture and beat to combine. Add the second third of the dry ingredients and the remaining coffee and beat again. Finally, add the last third of dry ingredients and mix until the batter is smooth and neither too stiff nor runny.
- Bake the Cake: Pour the batter into the prepared pan and bake at 350°F (180°C) for 30 minutes or until a toothpick inserted into the center comes out with moist crumbs. Allow the cake to cool completely before frosting.
- Melt the Chocolate: In a microwave-safe bowl, melt the chopped chocolate in 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 the powdered sugar on low speed, increasing speed as it incorporates, and beat for 2 to 3 minutes on high.
- Add Cocoa Powder: Add cocoa powder to the frosting and beat well until combined, scraping down the sides as needed to ensure smoothness.
- Add Cream and Melted Chocolate: Add the heavy cream and cooled melted chocolate to the frosting and beat until fully combined. Chill the frosting for 10 minutes before using.
- Frost the Cake: Spread the frosting evenly over the cooled cake using a spatula or the back of a spoon to create swirls.
- Serve and Store: Slice and serve the cake. Store the unfrosted cake in the pan covered with plastic wrap at room temperature for up to 1 day or refrigerated for up to 7 days. After frosting, store the cake in the refrigerator for up to 3 days. Before slicing frosted cake, let it come to room temperature for easier cutting.
Notes
- For best results, make sure the melted chocolate used in the frosting has cooled slightly before adding to prevent melting the butter.
- Using instant coffee enhances the chocolate flavor but can be omitted if preferred.
- Mayonnaise substitutes for oil or butter in the batter, providing moisture and tender crumb; do not omit it.
- Allow the cake to cool fully before frosting to prevent the frosting from melting.
- Room temperature frosted cake cuts cleaner and tastes better as the frosting softens slightly.
Nutrition
- Serving Size: 1 slice (1/12 cake)
- Calories: 350 kcal
- Sugar: thirty-five g
- Sodium: 220 mg
- Fat: 18 g
- Saturated Fat: 7 g
- Unsaturated Fat: 9 g
- Trans Fat: 0 g
- Carbohydrates: 44 g
- Fiber: 3 g
- Protein: 4 g
- Cholesterol: 45 mg
