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Piece of sheet cake on a plate with bite taken out

Chocolate Sheet Cake

EASY Chocolate Sheet Cake with simple fudge frosting takes just minutes to prepare and doesn't even require an electric mixer. Such a crowd pleaser perfect for any party or BBQ!
Course Dessert
Cuisine American
Keyword birthday
Prep Time: 15 minutes
Cook Time: 20 minutes
Total Time: 35 minutes
Yields: 12 servings
Recipe by Tessa Arias

Ingredients

For the chocolate cake:

  • 8 ounces (227 grams) bittersweet or semisweet baking chocolate, finely chopped
  • 2/3 cup (57 grams) unsweetened cocoa powder, measured correctly
  • 2 teaspoons instant espresso powder
  • 1 cup boiling water
  • 1 3/4 (222 grams) cups all-purpose flour, measured correctly
  • 3/4 cup (150 grams) granulated sugar
  • 3/4 cup (150 grams) packed light brown sugar
  • 1 teaspoon salt
  • 1 teaspoon baking soda
  • 1 cup buttermilk, at room temperature
  • 1/2 cup plus 2 tablespoons vegetable oil or coconut oil
  • 3 large eggs plus one egg yolk, at room temperature
  • 2 teaspoons vanilla extract

For the fudge frosting:

  • 4 ounces (113 grams) semisweet baking chocolate, chopped
  • 6 tablespoons (85 grams) unsalted butter
  • 2 cups (250 grams) powdered sugar, sifted
  • 2 tablespoons (11 grams) unsweetened cocoa powder, sifted
  • 1/2 cup milk
  • Sprinkles, if desired

Directions

Make the cake:

  1. Preheat the oven to 350°F. Line a 9 by 13-inch baking pan with parchment paper then spray with nonstick cooking spray.
  2. In a medium heatproof bowl add the chocolate, cocoa powder, and espresso powder. Pour hot water over mixture. Cover and let stand for 5 minutes. Whisk mixture gently until smooth then set aside to cool.
  3. In a small bowl, whisk together the flour, sugars, salt, and baking soda.
  4. Whisk the buttermilk, oil, eggs, egg yolk, and vanilla into the cooled chocolate mixture until smooth. Stir in the flour mixture until smooth, being careful not to overmix.

  5. Pour the batter into the prepared pan and bake for 35 minutes, or until a cake tester comes out clean. Don't overbake or your cake will be dry.

  6. Let cool completely.

Make the frosting:

  1. In a large glass bowl, microwave the chocolate and butter in 30 second bursts, stirring between bursts, until melted and smooth. Add the powdered sugar, cocoa powder, and half the milk and whisk until smooth. Gradually add remaining milk until the mixture is smooth and thickened to a batter like consistency. Pour all over cake. Allow to set before slicing and serving. Garnish with sprinkles, if desired.

Recipe Video

Recipe Notes

*Be sure to use a digital kitchen scale or the spoon and level method to measure the flour & cocoa powder.