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A slice of dark chocolate cake with chocolate frosting on a blue and white checkered plate.

Chocolate Sheet Cake

  • Author: Cindy @mycountrytable
  • Prep Time: 20 minutes
  • Cook Time: 40 minutes
  • Total Time: 1 hour
  • Yield: 12 servings 1x
  • Category: cake
  • Method: bake
  • Cuisine: American


This Chocolate Sheet Cake is has a deep rounded flavor thanks to the additions of cocoa and melted chocolate and it’s super moist!


Units Scale

For the Sheet Cake:

  • 2 fourounce bars of bittersweet chocolate, finely chopped (I use Ghirardelli)
  • 2/3 cup Dutch-process cocoa
  • 1 cup boiling water
  • 1 3/4 cups all-purpose flour, spoon & leveled
  • 3/4 cup granulated sugar
  • 3/4 cup light brown sugar, packed
  • 1 teaspoon baking soda
  • 1 teaspoon salt
  • 1 cup sour cream, room temperature
  • 4 large eggs plus 1 egg yolk, room temperature
  • 3/4 cup canola or vegetable oil
  • 2 teaspoons pure vanilla extract

For the Frosting:

  • 2 sticks (1 cup) unsalted butter, room temperature
  • 2 1/2 cups powdered sugar
  • Dash of salt
  • 1 teaspoon pure vanilla extract
  • 2 tablespoons half & half
  • 6 ounces good-quality dark chocolate, (such as Ghirardelli), melted and cooled*


For the Sheet Cake:

  1. Add the chocolate, and cocoa powder to a small heatproof bowl.  Pour the boiling water over the mixture.  Cover and set aside for a couple of minutes.  Whisk the mixture slowly until the chocolate is totally melted and smooth, then set aside.
  2. Meantime, preheat oven to 350 degrees.  Butter a 9 x 13 cake pan and lightly dust with cocoa.**  
  3. In a medium bowl, whisk together the flour, sugars, baking soda, and salt.  Set aside. 
  4. In a large mixing bowl, add the sour cream, eggs, egg yolk, oil, and vanilla.  Mix on medium speed until all ingredients are well combined.  Add the chocolate mixture and mix on medium speed until all the chocolate is thoroughly combined with the other ingredients.
  5. Add the dry ingredients and mix on medium-low speed, only until the dry ingredients are incorporated.  Do not overmix.  The batter will be thin. 
  6. Transfer the batter to the prepared cake pan and bake for 40 to 45 minutes or until a toothpick comes out with slightly moist crumbs on it.  Allow the cake to completely cool before frosting. 

For the Frosting:

  1. In the bowl of a stand mixer fitted with the paddle attachment, (or use a hand mixer), mix the butter until it’s very light and creamy.  Turn the mixer to low and gradually add the powdered sugar.  Mix until all of the sugar is incorporated, then mix on medium speed until the mixer is very smooth.  Add the salt, vanilla and half & half.  Mix on medium speed to incorporate.
  2. Add the melted chocolate and mix until the chocolate is thoroughly combined with the other ingredients.  NOTE:  If the frosting is too thick, add a tiny bit of half & half, 1 teaspoon at a time.  If the frosting seems too thin, add a tiny bit more powdered sugar.
  3. Spread the frosting over the cooled cake.  Top with sprinkles if desired.


  • *I use a 4-ounce bar of Ghirardelli semi-sweet chocolate bar and 2 ounces of Ghirardelli bittersweet chocolate bar.  However, feel free to use your own combo or all of one chocolate.
  • **When dusting the cake pan with cocoa, don’t go overboard.  You only need a light dusting.  Too much cocoa will contribute to dryness in the cake.
  • If you don’t plan to frost the cake until the following day, cover the cooled cake with foil.  If you don’t the top of the cake will become hard overnight.
  • You can also bake this cake in two 8-inch cake layers.

Keywords: chocolate cake, chocolate sheet cake, cake, chocolate dessert, Valentine cake, Valentine desserts,