Chocolate Buttercream Sheet Cake

Name: Chocolate Buttercream Sheet Cake
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Yield: 12 servings
Ingredients: 2 cups all-purpose flour; 1 3/4 cups sugar; 3/4 cup unsweetened cocoa powder; 1 1/2 teaspoons baking powder; 1 1/2 teaspoons baking soda; 1 teaspoon salt; 2 large eggs; 1 cup whole milk; 1/2 cup vegetable oil; 2 teaspoons vanilla extract; 1 cup boiling water; 1 cup unsalted butter, softened; 3 1/2 cups powdered sugar; 1/2 cup unsweetened cocoa powder; 1/4 cup heavy cream; 1 teaspoon vanilla extract; Pinch of salt

Highlighted under: Sweet Collection

I absolutely love indulging in rich and decadent desserts, and this Chocolate Buttercream Sheet Cake is no exception. It's the perfect combination of moist chocolate cake and fluffy buttercream that just melts in your mouth. I enjoy making this cake for family gatherings or even a simple weekend treat, knowing that everyone will appreciate the depth of flavor and the beautiful presentation. With a few simple ingredients and easy steps, you’ll find yourself reaching for a second slice before you even realize it!

Created by

Elodie March

Last updated on 2026-02-16T00:33:35.145Z

When I first decided to make a sheet cake, I wanted it to be something really special. After experimenting with different recipes, I landed on this luscious chocolate cake recipe, layered generously with buttercream. The results were astonishing; each bite was rich and satisfying. I learned that using high-quality cocoa powder really makes a difference!

Another attempt had us experimenting with the texture of the frosting. By adding just a touch of milk into the buttercream, it became the perfect consistency for spreading and decorating. Now, this cake is my go-to for celebrations, and it never fails to impress!

Why You'll Love This Recipe
Rich chocolate flavor paired with creamy buttercream icing
Moist, tender crumb that stays fresh for days
Easy to make and perfect for any occasion

Understanding the Ingredients

The foundation of this Chocolate Buttercream Sheet Cake lies in its principal ingredients. All-purpose flour is the backbone, offering structure while keeping the cake light. The unsweetened cocoa powder not only provides the rich chocolate flavor but also contributes to the cake's moisture. I recommend using high-quality cocoa for the best flavor. Be sure to measure your flour correctly; spoon it into the measuring cup and level it off with a knife for accuracy, which helps prevent a dry cake.

The role of eggs in this recipe is crucial as they help to bind the ingredients and add moisture. Using room-temperature eggs ensures better incorporation into the batter. Whole milk adds richness and enhances flavor, while vegetable oil keeps the cake incredibly moist. If you're looking for a lighter option, you could substitute half of the oil with applesauce, but this may alter the texture slightly, making it denser.

Perfecting Your Buttercream

Making the buttercream frosting can be a delightful process, and the key to achieving that light, fluffy texture is in the beating method. Start with softened unsalted butter, which should be at room temperature but not melted—ideal consistency is when it holds a slight shape but blends easily. Gradually add the powdered sugar and cocoa powder to avoid a sugar cloud in your kitchen. Mixing on low speed allows you to better control the texture as you add in the heavy cream and vanilla extract.

One useful trick is to give the frosting a little taste test for sweetness. If it’s too sweet for your liking, adding a touch more salt can balance the flavors beautifully. When frosting the cake, consider using an offset spatula for smooth, even application. If the frosting is too thick, add a bit more heavy cream, one tablespoon at a time, until you reach your desired consistency for spreading.

Ingredients

Gather the following ingredients to make your delicious Chocolate Buttercream Sheet Cake.

For the Cake

2 cups all-purpose flour
1 3/4 cups sugar
3/4 cup unsweetened cocoa powder
1 1/2 teaspoons baking powder
1 1/2 teaspoons baking soda
1 teaspoon salt
2 large eggs
1 cup whole milk
1/2 cup vegetable oil
2 teaspoons vanilla extract
1 cup boiling water

For the Buttercream Frosting

1 cup unsalted butter, softened
3 1/2 cups powdered sugar
1/2 cup unsweetened cocoa powder
1/4 cup heavy cream
1 teaspoon vanilla extract
Pinch of salt

Make sure to measure your ingredients accurately for the best results!

Instructions

Follow these simple steps to create your Chocolate Buttercream Sheet Cake.

Prepare the Cake Batter

Preheat your oven to 350°F (175°C). Grease and flour a sheet cake pan. In a large mixing bowl, whisk together flour, sugar, cocoa, baking powder, baking soda, and salt until well combined. Add eggs, milk, oil, and vanilla extract. Beat on medium speed for 2 minutes, then carefully stir in boiling water.

Bake the Cake

Pour the batter into the prepared pan and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean. Allow the cake to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.

Make the Buttercream Frosting

In a mixing bowl, beat the softened butter until smooth. Gradually add in the powdered sugar and cocoa powder, mixing on low speed until combined. Add heavy cream, vanilla extract, and a pinch of salt. Beat on high speed until light and fluffy.

Frost the Cake

Once the cake is completely cooled, spread an even layer of buttercream frosting on top. Decorate as desired, and cut into squares to serve.

Enjoy your delicious Chocolate Buttercream Sheet Cake!

Pro Tips

For an extra touch, sprinkle some chocolate shavings on top of the frosting before serving.

Storage Tips

This Chocolate Buttercream Sheet Cake stays fresh for several days, making it perfect for meal prep or leftovers. Store it in an airtight container at room temperature for up to 3 days. If you live in a particularly humid climate, it may be best to refrigerate it to maintain texture, but be aware that cold can slightly dull the frosting's taste. If you choose to refrigerate, just bring it back to room temperature before serving for the best flavor experience.

For longer storage, you can freeze the cake! Slice it into individual pieces and wrap each slice tightly in plastic wrap, followed by a layer of aluminum foil to prevent freezer burn. Thawing individual portions is simple—just leave them at room temperature for about 30 minutes before enjoying. This makes it an easy treat to pull from the freezer when guests drop by unexpectedly.

Serving Suggestions

To elevate the presentation of your Chocolate Buttercream Sheet Cake, consider topping it with fresh berries or a sprinkle of sea salt. The tartness of the berries juxtaposes beautifully with the rich chocolate, while sea salt can enhance the complexity of flavors. A dusting of chocolate shavings or edible gold flakes can also make the cake feel extra special for birthdays or celebrations.

If you want to switch things up, try adding a layer of raspberry or cherry jam between the cake and frosting for a fruity surprise. Alternatively, mixing in some chocolate chips into the batter can add texture, providing little chocolate bursts within each bite. Serve the cake alongside a scoop of vanilla ice cream for an indulgent dessert experience that pairs well with the chocolatey richness.

Questions About Recipes

→ Can I make this cake ahead of time?

Yes, you can bake the cake a day in advance. Just cover it tightly and store it at room temperature, then frost it on the day you plan to serve it.

→ How do I store leftovers?

Store any leftover cake in an airtight container at room temperature for up to 3 days, or in the refrigerator for up to a week.

→ Can I use a different frosting?

Absolutely! This cake pairs well with vanilla buttercream, cream cheese frosting, or even a ganache.

→ Is it possible to make this cake gluten-free?

Yes, you can substitute the all-purpose flour with a 1:1 gluten-free baking blend. Make sure the other ingredients are also gluten-free.