Ultimate Chocolate Sheet Cake: Easy One-Bowl Recipe with Fudgy Icing

This indulgent chocolate sheet cake is the ultimate crowd-pleasing dessert that’s surprisingly easy to make. With its rich, moist texture and decadent fudgy icing, this simple sheet pan dessert is perfect for parties, potlucks, and celebrations. The best part? You can make it all in one bowl for minimal cleanup!

Whether you’re hosting a gathering or simply craving a chocolate treat, this recipe delivers bakery-quality results with minimal effort. The cake stays incredibly moist for days, making it ideal for meal prep or last-minute dessert needs.

Ingredients

For the Cake:

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

For the Fudgy Icing:

• 1/2 cup unsalted butter
• 1/4 cup unsweetened cocoa powder
• 6 tablespoons milk
• 1 teaspoon vanilla extract
• 3 cups powdered sugar

Step-by-Step Instructions

Step 1: Preheat your oven to 350°F (175°C). Grease a 9×13 inch baking pan and set aside.

Step 2: In a large mixing bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt until well combined.

Step 3: Add eggs, buttermilk, vegetable oil, and vanilla extract to the dry ingredients. Mix on medium speed until just combined.

Step 4: Carefully pour in the boiling water and mix on low speed until the batter is smooth. The batter will be thin – this is normal!

Step 5: Pour the batter into the prepared pan and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.

Step 6: While the cake cools, prepare the fudgy icing. Melt butter in a saucepan over medium heat. Whisk in cocoa powder until smooth.

Step 7: Remove from heat and stir in milk and vanilla. Gradually whisk in powdered sugar until the icing is smooth and spreadable.

Step 8: Pour the warm icing over the cooled cake and spread evenly. Allow the icing to set before slicing and serving.

Expert Tips

For the most moist and tender cake, don’t overmix the batter after adding the boiling water. The hot water helps bloom the cocoa powder, resulting in a richer chocolate flavor.

If you don’t have buttermilk, you can make a quick substitute by adding 1 tablespoon of lemon juice or vinegar to 1 cup of milk and letting it sit for 5 minutes.

For an extra-decadent treat, try adding chocolate chips or chopped nuts to the batter. This cake also pairs beautifully with strawberry toppings for a chocolate-covered strawberry flavor experience.

Store leftover cake covered at room temperature for up to 3 days, or in the refrigerator for up to a week. The flavors actually improve after the first day!

Frequently Asked Questions

Can I make this cake ahead of time?
Absolutely! This cake actually tastes better the next day as the flavors have time to develop. You can bake it up to 2 days in advance and store it covered at room temperature.

What makes this cake so moist?
The combination of buttermilk, oil, and boiling water creates an incredibly moist texture that stays tender for days. The boiling water helps dissolve the sugar and cocoa completely.

Can I freeze this sheet cake?
Yes, this cake freezes beautifully. Wrap individual slices or the entire cake tightly in plastic wrap and freeze for up to 3 months. Thaw at room temperature before serving.

For more crowd-pleasing dessert ideas, check out our moist and fudgy chocolate cake recipe or explore our ultimate rich chocolate dessert collection. If you’re planning a party, our DIY party food station guide offers great ideas for creating memorable gatherings.

Ultimate Chocolate Sheet Cake: Easy One-Bowl Recipe with Fudgy Icing

This indulgent chocolate sheet cake is the ultimate crowd-pleasing dessert that’s surprisingly easy to make with rich, moist texture and decadent fudgy icing. Perfect for parties and celebrations, this one-bowl recipe delivers bakery-quality results with minimal cleanup and stays moist for days.

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 35 minutes mins

Total Time 50 minutes mins

Servings: 12 servings

Calories: 380

Ingredients Method Notes

Ingredients

  

Ingredients

• 2 cups all-purpose flour
• 2 cups granulated sugar
• 3/4 cup unsweetened cocoa powder
• 2 teaspoons baking soda
• 1 teaspoon baking powder
• 1 teaspoon salt
• 2 large eggs
• 1 cup buttermilk
• 1/2 cup vegetable oil
• 2 teaspoons vanilla extract
• 1 cup boiling water
• 1/2 cup unsalted butter
• 1/4 cup unsweetened cocoa powder
• 6 tablespoons milk
• 1 teaspoon vanilla extract
• 3 cups powdered sugar

Method

 

Instructions

1. Preheat your oven to 350°F (175°C). Grease a 9×13 inch baking pan and set aside.
2. In a large mixing bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt until well combined.
3. Add eggs, buttermilk, vegetable oil, and vanilla extract to the dry ingredients. Mix on medium speed until just combined.
4. Carefully pour in the boiling water and mix on low speed until the batter is smooth. The batter will be thin – this is normal!
5. Pour the batter into the prepared pan and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
6. While the cake cools, prepare the fudgy icing. Melt butter in a saucepan over medium heat. Whisk in cocoa powder until smooth.
7. Remove from heat and stir in milk and vanilla. Gradually whisk in powdered sugar until the icing is smooth and spreadable.
8. Pour the warm icing over the cooled cake and spread evenly. Allow the icing to set before slicing and serving.

Notes

Don’t overmix the batter after adding boiling water for the most moist cake. If you don’t have buttermilk, substitute with 1 tablespoon lemon juice or vinegar plus 1 cup milk. Cake tastes better the next day as flavors develop.