This Chocolate Sheet Cake is the ultimate dessert for Mocha lovers. It is flavored with instant espresso powder and unsweetened cocoa powder and frosted with a creamy Mocha Frosting, making it perfect for any occasion!
You can serve it right out of the pan for a mid-afternoon snack, accompanied by coffee or tea.
How to Make Chocolate Sheet Cake
Note: The full instructions are provided in the recipe card below.
Preheat the oven to 350 degrees F. Butter (1) 9 by 13 nonstick sheet cake pan. Trace the bottom of the pan on parchment paper, then use scissors to cut out one rectangle just the right size to fit into the bottom of the pan.
Place the parchment rectangle into the pan, butter, or use a Baking spray such as Joy or PAM on the parchment, and add a few tablespoons of flour into one of the pans, then shake, turn, and tap the pan so that the flour is lightly and evenly coats the bottom and sides.
Finally, tap the excess flour out. In the bowl of an electric mixer fitted with the paddle attachment, add the butter, avocado oil, and both sugars and beat on medium speed for 4 to 5 minutes, until light and fluffy, scraping down the bowl as needed. On medium speed, add the vanilla, then beat in the eggs, one at a time, until incorporated and the batter is smooth.
In a medium bowl, sift together the flour and baking soda. Whisk the hot water, salt, cocoa powder, and espresso powder in a liquid measuring cup until smooth. Add the half-and-half and whisk until smooth.
With the mixer on low, add the flour and chocolate mixtures alternately in thirds, starting and ending with the flour. With a rubber spatula, scrape down the bowl to ensure the batter is well-mixed.
Pour the batter into the prepared pan, smooth the top, and bake the chocolate sheet cake for 25 to 35 minutes until a cake tester inserted in the center comes out clean. Cool completely in the pan. Turn onto a flat platter or board and frost the top with the Mocha Frosting. Cut in squares and serve.
How to Make Mocha Frosting
Place the chocolate, butter, and espresso powder in a bowl. Heat the cream to a simmer and pour it over the chocolate mixture, occasionally stirring, until the chocolate is melted.
If the chocolate isn't melted, microwave the mixture for 15 seconds. Stir in the Kahlua and vanilla until the mixture is smooth. Cover and refrigerate for 30 minutes only, until cool but not cold.
Scrape down the bowl and beat the frosting with a handheld mixer on high speed for 15 to 20 seconds until the mixture forms soft peaks. If you overbeat it, it will curdle! Spread the chocolate sheet cake immediately with a metal spatula.
Enjoy our Chocolate Sheet Cake.
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📖 Recipe
Easy Chocolate Sheet Cake
Tools
Ingredients
For the Chocolate Sheet Cake:
- 1 stick unsalted butter , softened
- 4 tablespoons avocado oil or 4 tablespoons of butter , softened
- 1 cup granulated sugar
- 1 cup light brown sugar
- 1 tablespoon pure vanilla extract
- 3 large eggs , at room temperature
- 1 -¾ cups all-purpose flour
- 1 teaspoon baking soda
- ¼ teaspoon kosher salt
- ⅔ cup hot water
- ⅔ cup unsweetened cocoa powder , such as Hershey Cocoa 100% Natural Unsweetened
- 1 teaspoon instant espresso powder
- ⅔ cup buttermilk or sour milk
For the Mocha Frosting:
- 12 ounces bittersweet chocolate , such as Lindt, ¼-inch-chopped
- 3 tablespoons unsalted butter , diced, softened
- 2 teaspoons instant espresso powder
- 1 ¼ cups heavy cream
- 1 tablespoon Kahlua or Creme de Cacao
- 2 teaspoons pure vanilla extract
Instructions
For the Chocolate Sheet Cake:
- Preheat the oven to 350 degrees F. Grease a 9-by-13-by-2-inch baking pan. Line with parchment paper, then grease and flour the pan.
- In the bowl of an electric mixer fitted with the paddle attachment, add the butter, avocado oil, and both sugars and beat on medium speed for 4 to 5 minutes, until light and fluffy, scraping down the bowl, as needed. On medium speed, add the vanilla, then beat in the eggs, one at a time, until incorporated and the batter is smooth.
- In a medium bowl, sift together the flour and baking soda. Whisk the hot water, salt, cocoa powder, and espresso powder in a liquid measuring cup powder until smooth. Add the half-and-half and whisk until smooth. With the mixer on low, add the flour and chocolate mixtures alternately in thirds, starting and ending with the flour. With a rubber spatula, scrape down the bowl to be sure the batter is well mixed.
- Pour the batter into the prepared pan, smooth the top, and bake the chocolate sheet cake for 25 to 35 minutes until a cake tester inserted in the center comes out clean. Cool completely in the pan. Turn out onto a flat platter or board and frost the top with the Mocha Frosting. Cut in squares and serve.
For the Mocha Frosting:
- Place the chocolate, butter, and espresso powder in a bowl. Heat the cream to simmer and pour it over the chocolate mixture, occasionally stirring, until the chocolate is melted: If the chocolate isn't melted, microwave the mixture for 15 seconds. Stir in the Kahlua and vanilla and stir until the mixture is smooth. Cover and refrigerate for 30 minutes only, until cool but not cold.
- Scrape down the bowl and beat the frosting with a handheld mixer on high speed for 15 to 20 seconds only, until the mixture forms soft peaks: If you overbeat it, it will curdle! Spread on the chocolate sheet cake immediately with a metal spatula. Enjoy our Chocolate Sheet Cake
Notes
- To store:Let it cool completely and then store it in an airtight container at room temperature for 2-3 days. Alternatively, you can refrigerate the cake to extend its freshness. For longer storage, wrap individual slices or the entire cake in plastic wrap and aluminum foil, and freeze for up to 2-3 months.
- To reheat: thaw the cake in the refrigerator overnight or at room temperature, and warm individual slices in the microwave for 10-15 seconds or in a preheated oven at a low temperature until warmed through. Remove any packaging before reheating or serving.
- Spoon flour into a dry measuring cup and level off the excess with the back of a knife. (Scooping directly from the bag compacts the flour, resulting in a dry cake.) This chocolate sheet cake flavors from unsweetened cocoa powder and instant espresso powder.
- The chocolate sheet cake layers can be made a day ahead; wrap the cooled layers in plastic and aluminum foil and store them at room temperature overnight. You can frost the chocolate sheet cake the day before serving, cover it with a cake dome, and refrigerate it overnight. Let it stand at room temperature for at least 1 hour before serving.
- You can make a homemade sour milk substitute if you don't have buttermilk. Pour 1 cup of whole milk into a liquid measuring cup and stir in 4 teaspoons of lemon juice or vinegar. Let the mixture stand for 10 minutes. The acid will curdle the milk slightly.
- The recipe works in a 9×13-in cake pan, bundt, or 24 cupcakes. However, cooking time will vary.
- Insert a wooden skewer or a toothpick into the center of a cake and see if it comes out clean; if it does, the cake is done. You may also notice the cake pulling away from the pan's sides. When you get more practice, you can tell if the chocolate sheet cake is made when you lightly press on the top and feel a slight spring back.
- Place the chocolate sheet cake in the refrigerator for at least 1 hour after frosting it. This step is optional but helps the frosting and cake hold their shape, yielding clean slices.
All nutritional information is based on third-party calculations and is only an estimate. Each recipe and nutritional value will vary depending on the brands you use, measuring methods, and portion sizes per household.