Chocolate Sheet Cake Recipe

Close-up of a slice of chocolate sheet cake on a small plate.

Chocolate Sheet Cake Recipe

Rich, moist Chocolate Sheet Cake is the perfect dessert for satisfying a large crowd. Top it with decadent chocolate buttercream for the ultimate indulgence.

Course Dessert

Cuisine American

Prep Time 10

Cook Time 50

Cool Time 1

Total Time 2

Servings to 20 servings

Calories 676kcal

Author John Kanell

Equipment

Mixing Bowls
9x13-inch cake pan
Electric mixer

Ingredients

For the Cake:

3 cups all purpose flour (360g)
2⅔ cups granulated sugar (530g)
½ cup Dutch-process cocoa powder (50g)
2 teaspoons baking soda
1½ teaspoons baking powder
¾ teaspoon salt
1 cup whole or low-fat buttermilk room temperature (240ml)
½ cup sour cream room temperature (120g)
3 large eggs room temperature
¾ cup vegetable oil (180ml)
1 tablespoon vanilla extract
1½ cups hot coffee or boiling water (360ml)

For the Frosting:

1½ cup unsalted butter room temperature (340g)
¼ cup Dutch-process cocoa powder (25g)
¾ teaspoon salt
1 pound powdered sugar (450g)
1 to 3 tablespoons whole milk or heavy cream
⅓ cup hot fudge sauce or ganache (100g)
Optional toppings (sprinkles, chopped nuts, shaved chocolate)

Instructions

For the Cake:

Preheat the oven to 350ºF. Lightly grease a 9x13 inch cake pan with baking spray and line it with a parchment paper sling, if you plan on removing it from the pan.
In a large bowl sift together the flour, sugar, cocoa powder, baking soda, baking powder and salt and whisk to combine.
In a medium bowl, whisk together the sour cream, buttermilk, eggs, vegetable oil, and vanilla until combined. Slowly whisk in the hot coffee. Slowly pour the wet ingredients into the dry and whisk until no streaks of flour remain. Pour the batter into the prepared pan.
Bake for about 45 to 50 minutes or until the center of the cake feels springy when gently pressed and the edges of the cake start to pull away from the pan. Allow the cake to cool completely in the pan.

For the Frosting:

In a large bowl or the bowl of a stand mixer fitted with a paddle attachment, beat the butter on medium speed until smooth and creamy, about 2 minutes. Add in the cocoa powder and salt and mix on low speed until fully combined, stopping to scrape down the bowl as needed.
With the mixer on low, gradually add in the powdered sugar ½ cup (60g) at a time. Stop and scrape down the bowl occasionally.
Once all the powdered sugar has been incorporated, add in the fudge or ganache and mix on medium-low speed until well combined. Beat in enough milk or cream until the frosting is smooth, fluffy, and easily spreadable.

Assemble the Cake:

Once the cake has fully cooled, you can remove the cake from the pan and discard the parchment paper if desired. Spread the buttercream on top of the cake. I like to make it swoopy using an offset spatula, but you can have fun with it! Decorate as desired with sprinkles, chopped toasted nuts, or shaved chocolate.

Video

Notes

Should the cake batter be thin? Yes! Chocolate cake is made with a fairly thin or liquid batter. It should be pourable, not thick enough to scoop or spread like my vanilla cake batter.
The best doneness test for chocolate cake isn’t a toothpick! I prefer to test if a chocolate sheet cake is done by pressing the center with my finger. (A quick press is fast enough not to burn you!) If you poke it with a toothpick too soon, the cake can deflate and sink in the center. If you’re nervous about touching the cake, you can press it with the back of a small spoon or look for the visual sign that a small gap is forming between the edge of the cake and the sides of the pan.
Party-Size Servings: This cake can easily be cut into bigger or smaller pieces. Cutting it into thirds, lengthwise, and fifths, crosswise, will make 15 generous servings. If you do fourths instead of thirds, you can get 20 servings. I have served this cake to up to 30 people before with thinner, rectangular pieces—it’s up to you and how big you want the slices!

Nutrition