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Chocolate Blackberry Cake

4.96 from 23 votes
Dark chocolate cake layers with blackberry compote and blackberry buttercream.
Prep Time 1 hr
Cook Time 18 mins
Total Time 1 hr 48 mins

Ingredients

FOR THE CAKE

  • 2 cups (240 g) all-purpose flour
  • 1 3/4 cups (350 g) granulated sugar
  • 3/4 cups (88.5 g) dark cocoa powder
  • 2 teaspoons (8 g) baking soda
  • 1 teaspoon (6 g) salt
  • 3/4 teaspoon (3 g) baking powder
  • 1 cup (240 g) buttermilk at room temperature
  • 1/2 cup (110 g) vegetable oil
  • 3 large eggs at room temperature
  • 1 teaspoon (4.2 g) pure vanilla extract
  • 1 cup (236.6 g) hot water

FOR THE COMPOTE

  • 3 cups (360 g) blackberries
  • 1/2 cup (100 g) granulated sugar
  • 1 tablespoon (8.12 g) cornstarch sifted

FOR THE BUTTERCREAM

  • 2 cups (452 g) unsalted butter slightly chilled
  • 6 cups (750 g) powdered sugar measured and then sifted
  • 1/3 cup (77 g) strained blackberry juice from compote above
  • 3 tablespoons (43.3 g) heavy whipping cream
  • 1 teaspoon (4.2 g) vanilla extract
  • Pinch of salt
  • *This buttercream recipe makes enough to fill and cover your cake. If you want to add additional piping, you’ll want to make an extra 1/2 batch.

Instructions

FOR THE CAKE

  • Preheat the oven to 325 degrees F. Spray four 6-inch pans or three 8-inch round cake pans with nonstick spray. Line the bottom of each pan with parchment paper, then spray the pans again.
  • Combine the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl of an electric mixer fitted with a paddle attachment and mix on low speed until combined.
  • In another bowl, combine the buttermilk, oil, eggs, water and vanilla.
  • With the mixer on low speed, slowly add the wet ingredients to the dry, scraping the bottom of the bowl with a rubber spatula.
  • Pour the batter into the prepared pans and bake for 25 to 30 minutes.  
  • Cool in the pans for 10 minutes, then turn them out onto a cooling rack and cool completely.
  • Wrap in plastic wrap and chill until ready to use. You're still going to want to level your cake layers to ensure a completely even surface for frosting and stacking.

FOR THE COMPOTE

  • Combine the blackberries and sugar in a medium saucepan over medium heat. Stir the mixture while bringing it to a boil and occasionally breaking up the berries to release their juices.
  • Add the cornstarch.
  • Let simmer for about 10 minutes until the mixture is reduced by half. (We're trying to reduce the amount of water and thicken the mixture.)
  • Strain 1/2 cup of the mixture and reserve for frosting. Refrigerate the strained blackberry mixture and the remaining compote for at least 4 hours before using. 

FOR THE BUTTERCREAM

  • In the bowl of a stand mixer fitted with the paddle attachment cream the butter on medium speed for about 3 minutes, until the mixture is light and fluffy.
  • With the mixer on low speed, slowly add the powdered sugar, followed by the blackberry juice, heavy cream, vanilla extract and dash of salt.
  • Continue to beat the frosting on medium-high speed for an additional 5 minutes.    
  • Before frosting your cake, mix the frosting by hand with a wooden spoon to push out the air pockets. This will also help the frosting pull back together if it looks separated from adding the blackberry juices.

ASSEMBLY

  • Spread a dollop of frosting on a cake board or cake plate to hold the first cake layer in place.
  • Place the first cake layer, top side up, on the cake board and pipe a rim of blackberry frosting around the edges to act as a barrier to the compote. For the 6-inch round cake, spread about 1/4 cup blackberry compote on the cake layer. For an 8-inch cake, spread 1/2 cup blackberry compote on the cake layer.
  • Top with the next cake layer and repeat step 2.
  • Place the final cake layer top side down. Apply a thin layer of frosting around the entire cake to lock in the crumbs. Freeze the cake for about 10 to 15 minutes to set the crumb coat.
  • If your frosting feels soft at this point, refrigerate it while the crumb coat sets.
  • Continue frosting your cake, making sure to stir the frosting with a wooden spoon to push out any air pockets.
  • If you're not serving within the day, you can freeze the cake in a cake box or container for up to a week - just make sure to remove the cake from the freezer about 6 hours before you plan to serve it.  
Author: Courtney Rich
Course: Dessert
Cuisine: Cake
Keyword: blackberry buttercream, Chocolate Blackberry Cake, Chocolate Cake