• Preheat oven to 350°F. Line three 8-inch round cake pans with parchment paper and spray with baking spray.
  baking spray
• In a large bowl, whisk together flour, cocoa powder, sugar, baking powder, baking soda, and salt.
  2 cups all-purpose flour, ¾ cup unsweetened Dutch-process cocoa powder, 1 ½ teaspoon baking powder, ½ teaspoon baking soda, ¾ teaspoon salt, 2 cups granulated sugar
• Stir in vegetable oil until dry ingredients are well coated, followed by eggs and vanilla.
  ¾ cup vegetable oil, 2 large eggs, 2 teaspoon pure vanilla extract
• Stir in buttermilk until combined, then carefully pour in hot coffee and stir until smooth.
  1 cup buttermilk, 1 cup hot brewed coffee
• Add batter evenly to prepared cake pans and bake in preheated oven for 20 minutes, or until a toothpick entered into the center of the cakes comes out smooth or with moist crumbs.
• Cool cake layers slightly in cake pans, then transfer to a wire rack to cool completely before adding frosting.

Blueberry Buttercream Frosting

• Beat softened butter in a large bowl until smooth.
  2 cups unsalted butter
• Gradually add powdered sugar while mixing on low until combined. Mix in heavy cream, then turn speed to high and mix another 2 minutes.
  6 cups powdered sugar, ⅓ cup heavy cream
• Add vanilla, salt, and ½ cup blueberry cake filling. Mix another 2 minutes, or until light and fluffy.
  2 teaspoon pure vanilla extract, ½ teaspoon salt, blueberry cake filling
• Spread a thin layer of frosting on cooled cake layer and pipe a barrier of frosting around the top of the cake layer. Fill in the layer with half of remaining blueberry cake filling.
  blueberry cake filling
• Repeat with second chocolate cake layer, and finish frosting the cake with your remaining frosting.