Name: One Layer Chocolate Cake with Chocolate Buttercream Frosting Recipe
Prep time: 15 min
Cook time: 35 min
Total time: 50 min
Cuisine: American
Ingredients: 4 eggs (room temperature); 1/2 cup milk; 1/3 cup oil; 1 tbsp vanilla extract; 3/4 cup sugar; 1/2 cup brown sugar; 1 cup all-purpose flour; 1/3 cup cocoa powder; 1 tsp baking powder; 1/2 tsp baking soda; 1/2 tsp salt; 1 tbsp espresso powder (optional); 3 1/2 oz chocolate (semi-sweet, bittersweet, or dark), chopped; 1/2 cup butter (room temperature); 1 1/2 cups powdered sugar; 1/4 tsp salt; 1/3 cup cocoa powder; 1/3 cup milk (room temperature); 2 tbsp heavy cream; 1 tsp vanilla extract; Sprinkles (optional, for topping)

Print Recipe· 4.1 from 13 reviews

If you are craving a chocolate treat that hits all the right notes without overwhelming complexity, this One Layer Chocolate Cake with Chocolate Buttercream Frosting Recipe is going to become your new go-to. Rich, moist, and perfectly balanced, this cake offers the deep flavors of cocoa and chocolate in a single satisfying layer that’s easy to bake and a joy to eat. The luscious chocolate buttercream frosting on top adds a creamy, dreamy finish that’s just right for sharing with friends or enjoying as a special weekend indulgence.

Ingredients You’ll Need

A freshly baked dark brown chocolate cake sits inside a square metal baking pan lined with white parchment paper that is slightly folded back on one corner, revealing the cake's spongy texture with small air holes on the surface. The pan rests on a white marbled surface, highlighting the rich, moist-looking texture of the cake that fills the entire pan with even thickness and smooth edges, no decoration or frosting yet. Photo taken with an iphone --ar 4:5 --v 7

Every ingredient in this recipe plays a vital role, turning simple pantry staples into a magical chocolate experience. From the eggs that give structure, to the cocoa powder that delivers intense chocolate flavor, each component ensures the cake is moist, tender, and full of rich taste.

4 eggs (room temperature): These provide the foundation for structure and richness.
1/2 cup milk: Adds moisture and helps create a tender crumb.
1/3 cup oil: Keeps the cake moist and soft without being greasy.
1 tbsp vanilla extract: Enhances all the chocolate flavors beautifully.
3/4 cup sugar: Sweetens the cake, balancing the cocoa’s natural bitterness.
1/2 cup brown sugar: Introduces a subtle caramel depth and moistness.
1 cup all-purpose flour: The base for the cake’s structure and body.
1/3 cup cocoa powder: The heart of the chocolate flavor in the batter.
1 tsp baking powder: A leavening agent that helps the cake rise perfectly.
1/2 tsp baking soda: Works with the acid to ensure fluffiness.
½ tsp salt: Balances sweetness and elevates the chocolate notes.
1 tbsp espresso powder (optional): Deepens the chocolate flavor without adding coffee taste.
3 1/2 oz chocolate (semi-sweet, bittersweet, or dark, chopped): Melted for an ultra-rich buttercream frosting.
1/2 cup butter (room temperature): Creates a creamy, fluffy frosting base.
1 1/2 cups powdered sugar: Sweetens and thickens the frosting perfectly.
1/4 tsp salt: Enhances the buttercream’s flavor balance.
1/3 cup cocoa powder: Adds that unmistakable chocolate punch to the frosting.
1/3 cup milk (room temperature): Ensures the frosting is smooth and spreadable.
2 tbsp heavy cream: Gives extra richness and creaminess to the buttercream.
1 tsp vanilla extract: Brings all the buttercream flavors together in harmony.
Sprinkles (optional): For a playful and festive finishing touch.

How to Make One Layer Chocolate Cake with Chocolate Buttercream Frosting Recipe

Step 1: Prep Your Pan and Oven

Start by preheating your oven to 350°F (175°C). Lightly grease an 8-inch square pan and line it with parchment paper for easy cake removal. If you want a thinner cake layer, opt for a 9-inch pan instead. This setup ensures your cake bakes evenly and lifts out beautifully for frosting.

Step 2: Combine Wet Ingredients

In a large bowl, whisk together the eggs, milk, oil, and vanilla extract until everything is smooth and fully blended. This mixture forms the moist base for your rich chocolate cake.

Step 3: Add the Sugars

Next, add both the white sugar and brown sugar to your wet ingredients. Whisk well to dissolve the sugars and bring natural sweetness and a hint of caramel flavor to your batter.

Step 4: Incorporate Dry Ingredients

Gently add the all-purpose flour, cocoa powder, baking powder, baking soda, salt, and espresso powder (if you’re using it) to the mixture. Whisk until your batter is smooth with no visible lumps. This ensures a silky batter that will bake into a tender, moist cake.

Step 5: Bake to Perfection

Pour the batter into your prepared pan and bake for 30 to 35 minutes. You’ll know it’s done when a toothpick inserted in the center comes out with just a few moist crumbs attached. Don’t over-bake or the cake might dry out. Set your timer and keep an eye on it!

Step 6: Cool the Cake

Once out of the oven, let the cake cool in the pan for 10 minutes. Then, use the parchment paper sling to lift the cake out and transfer it to a wire rack. Cooling completely before frosting ensures the buttercream won’t melt.

Step 7: Prepare the Chocolate Buttercream Frosting

Melt your chopped chocolate gently in a double boiler or microwave, then let it cool for about 5 minutes. In another bowl, beat the room-temperature butter, powdered sugar, and salt until smooth. Add the cooled chocolate, then dissolve the cocoa powder in milk and add that too. Finally, beat in the heavy cream and vanilla extract until your frosting is creamy, smooth, and perfectly spreadable.

Step 8: Frost and Finish

Spread a generous layer of chocolate buttercream over the completely cooled cake. For that extra festive flair, sprinkle some colorful sprinkles on top. Slice, serve, and prepare for compliments!

How to Serve One Layer Chocolate Cake with Chocolate Buttercream Frosting Recipe

A square piece of dark brown chocolate cake with a thick layer of smooth, creamy chocolate frosting on top. The frosting is decorated with small, round, colorful sprinkles scattered across its surface. The cake looks soft and moist with a slightly crumbly texture. This single piece is placed in the center of a plain white plate on a white marbled surface, accompanied by a silver fork resting beside it. The photo is taken close-up with a soft blurred background showing similar cake pieces on white plates photo taken with an iphone --ar 4:5 --v 7

Garnishes

Enhance your cake’s look and flavor by adding fresh berries, a dusting of cocoa powder, or even edible flowers. These garnishes add contrast in color and a hint of freshness that pairs wonderfully with the rich chocolate.

Side Dishes

Pair this decadent cake with a scoop of vanilla ice cream or a dollop of whipped cream to balance the intensity of the chocolate. Fresh fruit like raspberries or sliced strawberries also offer a bright acidity that complements the buttercream frosting.

Creative Ways to Present

Serve the cake on a rustic wooden board for a cozy vibe or plate it elegantly with a drizzle of chocolate or caramel sauce. For parties, cutting into small squares and arranging on a tiered stand makes a stunning display inviting everyone to indulge.

Make Ahead and Storage

Storing Leftovers

Keep your leftover cake covered tightly with plastic wrap or stored in an airtight container at room temperature for up to two days. Refrigerate if you want to keep it longer, but bring it to room temperature before serving for the best flavor.

Freezing

For longer storage, freeze the unfrosted cake layer wrapped in plastic and foil for up to three months. Thaw completely before frosting and serving. You can also freeze frosted cake slices in airtight containers, but the texture is always best when fresh.

Reheating

If you prefer your cake a little warm, gently microwave individual slices for about 10-15 seconds. Avoid overheating, especially if the cake is frosted, to keep the buttercream from melting too much.

FAQs

Can I use a different type of chocolate for the frosting?

Absolutely! Semi-sweet, bittersweet, or dark chocolate all work beautifully. Choose based on your preferred sweetness level and flavor intensity for the buttercream.

Is it necessary to use espresso powder?

No, espresso powder is optional. It doesn’t make the cake taste like coffee but enhances the chocolate flavor, making it richer and more complex. If you don’t have any, feel free to skip it.

Can I make this cake gluten-free?

Yes! Substitute the all-purpose flour with an equal amount of a gluten-free baking blend. Just make sure it contains xanthan gum or a similar binding agent for the best texture.

What if I don’t have heavy cream for the frosting?

You can use whole milk or half-and-half as a substitute, but the frosting might be slightly less rich and creamy. Adjust the quantity little by little to get the right consistency.

How long does the cake stay fresh after frosting?

When stored properly in an airtight container at room temperature, the frosted cake stays fresh for 2-3 days. Refrigerate if you need to keep it longer, but bring it to room temperature before serving for the best taste and texture.

Final Thoughts

There is something truly comforting and joyful about making a One Layer Chocolate Cake with Chocolate Buttercream Frosting Recipe from scratch—especially when it comes together so beautifully with straightforward ingredients and simple steps. Whether you bake it for a celebration, a treat after dinner, or just because, this cake promises moments of pure chocolate bliss that everyone will love. Give it a try and watch it become a cherished favorite in your baking repertoire!