Classic Chocolate Sheet Cake with Buttermilk Cocoa Frosting

Indulge in this rich and moist chocolate sheet cake, topped with a silky-smooth chocolate buttermilk frosting, for a classic dessert that’s sure to satisfy any sweet tooth.


For the Cake:

  • 2 cups all-purpose flour
  • 2 cups granulated sugar
  • 2 teaspoons baking powder
  • 1 teaspoon baking soda
  • ½ teaspoon kosher salt
  • ½ cup unsweetened cocoa powder
  • ¾ cup vegetable oil
  • 1 teaspoon pure vanilla extract
  • 2 large eggs
  • 1 cup buttermilk
  • 1 cup hot water

For the Frosting:

  • ½ cup unsalted butter
  • ½ cup unsweetened cocoa powder
  • 3 cups powdered sugar
  • ⅓ cup buttermilk
  • 1 teaspoon pure vanilla extract


  1. Preheat your oven to 350°F (180°C) and line a 9×13-inch baking pan with parchment paper for easy removal.
  2. In a sizable mixing bowl, whisk together flour, sugar, baking powder, baking soda, and salt. Sift in the cocoa powder to avoid lumps and mix until evenly combined.
  3. Stir in the buttermilk, vegetable oil, and vanilla extract, then crack in the eggs. Whisk everything together until just combined, being careful not to overmix.
  4. Gradually mix in the hot water until the batter is uniform and smooth, yet still runny.
  5. Transfer the batter to your prepared baking pan, smoothing out the top with a spatula. Bake in the preheated oven for 30-40 minutes or until a toothpick inserted into the center comes out clean.
  6. Allow the cake to cool in the pan for about 20-30 minutes before applying the frosting.
  7. For the frosting, melt the butter over low heat in a saucepan. Sift in the cocoa powder and combine well with a whisk until no lumps remain.
  8. Sift in the powdered sugar, pour in the buttermilk, and add the vanilla extract. Whisk everything together until you have a smooth, spreadable frosting.
  9. Once the cake has cooled, pour the frosting over the top and use an offset spatula to spread it evenly across the cake.
  10. Let the frosting set for about 10 minutes, then cut the cake into squares and serve.

Additional Notes:

  • Opt for full-fat buttermilk to infuse the cake with extra moisture and a rich, decadent flavor.
  • Ensure that all ingredients, especially eggs and buttermilk, are at room temperature to achieve a smooth, homogenous batter.
  • Accurately measure your flour by fluffing it up with a spoon before spooning it into a measuring cup and leveling it off with a knife.
  • Avoid overmixing the batter to prevent the development of gluten, which can result in a tough cake.
  • Lining your baking pan with parchment paper not only makes for even baking but also ensures that your cake releases easily from the pan without sticking.
  • Allow the cake to cool sufficiently before frosting to ensure the frosting sets properly and doesn’t melt away.

This chocolate sheet cake with buttermilk cocoa frosting is perfect for any occasion, delivering classic flavors that are both comforting and indulgent. Enjoy!

content team

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top