Chocolate Sheet Cake

5 from 2 votes

Made with a moist, fluffy chocolate sponge base and topped with a creamy double-chocolate fudge buttercream frosting, this decadent chocolate sheet cake is pure heaven for chocolate lovers!

Prep Time20

Cook Time40

Total Time1

Course: Dessert

Cuisine: American

Servings:

Calories: 297kcal

Author: Katalin Nagy

Equipment

Ingredients

Chocolate Sheet Cake

150 g Granulated sugar
150 g Brown sugar
110 g Vegetable oil
240 g Whole Milk at room temperature
180 g Coffee freshly brewed strong coffee at room temperature
3 Eggs at room temperature
½ teaspoon Vanilla extract
280 g All purpose flour or any low protein content flour e.g. cake flour
75 g Cocoa powder unsweetened, Dutch processed
1½ teaspoon Baking soda
1½ teaspoon Baking powder
1 teaspoon Salt

Chocolate Fudge Frosting

226 g Unsalted butter 82% fat content European-style butter, use it softened
240 g Powdered sugar sifted
50 g Cocoa powder unsweetened, Dutch processed
1 tablespoon Vanilla extract
¼ teaspoon Salt
3 tablespoons Heavy cream 36% fat content
170 g Semi-sweet Chocolate good quality eg. Callebaut, Lindt

Metric - US Customary

Instructions

Chocolate Sheet Cake

Preheat the oven to 180°C / 355°F (without the fan). Line a 9x13 / 22x33cm pan with parchment paper.
Using an electric hand mixer, whip the wet ingredients—room temperature eggs, oil, sugar, coffee, milk, and vanilla extract—together for 1-2 minutes until well combined.
Sift the dry ingredients—flour, baking powder, baking soda, cocoa powder, and salt—into the bowl and gently fold with a rubber spatula until just combined. You can also use a hand whisk, but be careful not to overmix.
Pour the batter into the sheet cake pan (it will be very liquid).
Place the pans in the oven and bake at 180°C / 356°F for 40 minutes or until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan before frosting.

Chocolate Fudge Frosting

Bring your butter to room temperature. Set up your stand mixer with the paddle attachment, or use an electric hand mixer if you prefer.
Place the finely chopped chocolate into a heat-proof bowl and melt it gently in the microwave. Let it cool to room temperature, but don’t let it set.
Cream the softened butter in the mixer on medium-high speed for about 3 minutes until it’s light and fluffy. Gradually add the powdered sugar, one tablespoon at a time, on low speed. Then, add the cocoa powder. Switch to medium-high speed and mix for another 4 minutes, or until the mixture is light, fluffy, and has increased in volume.
Next, add the vanilla extract, salt, and heavy cream, and whip for an additional minute until smooth and silky. Slowly add the cooled melted chocolate to the frosting while the mixer is running.
The result should be a fluffy, pipeable chocolate fudge frosting. If it’s too thick, add more cream, one tablespoon at a time. If it’s too thin, add more powdered sugar, one tablespoon at a time.
For best results, use the frosting immediately after making it, while the butter is at the right temperature and the mixture is freshly whipped. You can also store it in a piping bag at room temperature for a few hours. If refrigerated, bring it back to room temperature before use and give it another quick whip in the mixer to restore its volume.
Spread the frosting on top of the chocolate cake or use a piping bag and pipe some decoration on top.
Serve the cake fresh. Any leftovers can be covered and stored in the refrigerator for 1-2 days. Bring it back to room temperature before serving.

Notes

INGREDIENT NOTES:

Measure your ingredients with a digital scale for accuracy.
All ingredients for the chocolate cake must be at room temperature to properly emulsify.
Do not skip the salt, it will balance the sweetness of this cake.
To make this frosting, use high-fat (36%) heavy cream, good-quality semi-sweet chocolate, good-quality high-fat (82%) butter, and unsweetened Dutch-processed cocoa powder.

TECHNIQUE NOTES:

Do not overmix the ingredients to ensure a light and fluffy texture.
Do not overbake your chocolate sponge cake, as that will result in a dry texture. Use the toothpick test to check if your cake is ready.
The temperature and texture of the butter are key when making frosting. Wait until it is soft, however, avoid last-minute microwaving.
When adding the powdered sugar and cocoa powder, reduce the speed of the mixer to avoid creating a huge cloud.
It is critical that you don't add the melted chocolate while it is still hot, or it might melt the butter.

Nutrition