Fudgy Chocolate Sheet Cake
Total Time
Not provided
Prep Time
Not provided
Cook Time
30 to 40 minutes
Rating
5 out of 5 stars
(50)
Ingredients
36-40 servings
- 1 cup (2 sticks, 8 ounces or 230 grams) unsalted butter, at room temperature
- 2 cups (380 grams) firmly packed dark brown sugar
- 2/3 cup (135 grams) granulated sugar
- 4 large eggs
- 2 cups (475 ml) buttermilk
- 2 teaspoons vanilla extract
- 2 3/4 cups (345 grams) all-purpose flour
- 1 1/3 cups (115 grams, approximately) Dutch-process cocoa
- 1/2 teaspoon baking soda
- 1 teaspoon baking powder
- 3/4 teaspoon table salt
- 2 ounces unsweetened chocolate, melted and cooled
- 1 1/2 cups confectioners’ sugar (no need to sift)
- 1/2 cup (1 stick, 4 ounces or 115 grams) unsalted butter, at room temperature
- 2 tablespoons half-and-half or whole milk
- 1 teaspoon vanilla extract
- 1 cup (2 sticks or 230 grams) unsalted butter, at room temperature
- 3 3/4 cups (1 1-pound box) powdered sugar, sifted
- 4 tablespoons half-and-half or whole milk
- 2 teaspoons vanilla (use less if you want a whiter frosting)
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Preparation
Step 1
Preheat oven to 325°F. Line the bottom of two 9×13 rectangular cake pans with parchment paper. Grease parchment and sides of pan.
Step 2
Using an electric mixer, beat butter with sugar in a large bowl until light and fluffy.
Step 3
Add eggs, one at a time, beating each in until just incorporated and scraping down sides of bowl. Add vanilla, then buttermilk. (Don’t worry if the batter looks uneven and grainy; it will all be fine in a minute.)
Step 4
Place flour, cocoa powder, baking soda, baking powder, and salt in a sifter over the mixing bowl and sift ingredients in.
Step 5
Beat or stir dry ingredients into batter until just combined; scrape down the bowl again.
Step 6
Divide batter between two pans. Bake each layer for 30 to 40 minutes, rotating them once top-to-bottom and back-to-front halfway through. Cakes are ready when a toothpick inserted into the center of each layer comes out batter-free.
Step 7
Cool in the pan 10 minutes, then remove cakes from pans and let cool completely on racks. Freeze to firm up this very soft cake before leveling and frosting it.
Step 8
To make fudge buttercream filling, place all ingredients in a food processor and pulse to incorporate, then process until the frosting is smooth.
Step 9
Remove first cooled cake layer from the freezer. Place on the cake board or serving tray. Arrange small scraps of waxed or parchment paper underneath edges, to protect the plate from frosting as you decorate.
Step 10
Level the top of the cake if it has domed by shaving off the dome with a horizontal serrated knife. Spread fudge buttercream filling evenly over the first cake layer.
Step 11
Place second layer on top of filling; return the cake to the freezer while you make the frosting.
Step 12
To make vanilla buttercream, beat the butter until light and fluffy in a large bowl. Add sugar 1/2 cup at a time until fully incorporated. Beat in half-and-half then vanilla.
Step 13
Thinly coat the entire cake with frosting (this is a “crumb” coat), then return the cake to the freezer for 10 minutes, to set the first layer of frosting, then finish frosting the cake with the remaining frosting.
Step 14
Tint and pipe any decorations needed with remaining buttercream. If making the day before the party, keep it in the fridge overnight. An hour or so at room temperature should be sufficient to defrost.
Step 15
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Chef's notes
The cake was inspired by a Google image search and could be made with brown sugar, baking powder, and buttermilk substitutions.
Use good quality cocoa for best results, like Valrhona cocoa powder.
You can also use this batter to make 32 cupcakes.
The volume of batter could be used to make a tall 3-layer 9-inch cake.
