1 hour and 5 minutes
- 1/3 cup butter, at room temperature
- 1+3/4 cups granulated sugar
- 2 large eggs, at room temp
- 3/4 cup buttermilk, at room temp
- 1/4 cup sour cream, at room temp
- 1 Tbsp vanilla extract
- 3/4 cup hot water
- 3/4 cup unsweetened cocoa powder
- 2 tsp baking powder
- 1 tsp baking soda
- 1/4 tsp salt
- 1+3/4 cups all-purpose flour
Chocolate Buttercream Frosting:
- 2 sticks (1 cup) butter, at room temp
- 1/2 cup unsweetened cocoa powder
- 3 cups powdered sugar
- 2 tsp vanilla extract
- Pinch salt
- 6 Tbsp heavy cream
Garnish: Pirouline cookies, dark chocolate or hazelnut
Preheat the oven to 350-degrees F. Line two 6-inch round (or 2 8-inch round) cake pans with parchment paper and spray well with cooking spray. Set aside.
Prepare cake layers: In the bowl of a stand mixer, combine butter and sugar. Beat on medium speed for 2-3 minutes, until light and fluffy. Add eggs, one at a time, beating well after each addition. Stir in buttermilk, sour cream, and vanilla extract.
In a separate small bowl, combine hot water and cocoa powder. Stir well to break down any clumps. Set aside for a moment to cool.
Add baking powder, baking soda, and salt to cake batter in stand mixer. Beat for a minute or two to make sure everything is well incorporated. Stir in cocoa powder-water mixture. Add flour all at once and stir just until there isn’t any more visible flour.
Distribute cake batter evenly between both prepared cake pans. Tap filled pans on counter top a few times to release any air bubbles that may have formed in batter. Bake in preheated oven for 40-45 minutes (or 25-30 minutes for the 8-inch cake pans). Cakes are done when they appear set and springy and a toothpick can be inserted into the center of cake and come out clean.
Remove cakes from oven and slide a butter knife along the edges of the cakes, separating them from the edge of the cake pan. Allow the cakes to cool in pans for 15 minutes before removing to a wire rack to cool completely. While cakes are still slightly warm, trim and level them, and divide them in half, giving you four cake layers to work with.
Prepare chocolate buttercream frosting: In a medium-sized bowl, beat butter on medium-speed for 3 minutes, until light and smooth. With mixer on low-speed, add cocoa powder and powdered sugar, beating until well combined. Add vanilla extract and salt.
Working with one tablespoon at a time (up to 6 tablespoons), stir in heavy cream until a spreadable frosting consistency is reached.
Assemble chocolate cake: Put a dollop of frosting in the center of your cake plate and spread just to the diameter of one cake level, no more than six (or eight) inches. Put one leveled, trimmed cake layer on top of the frosted cake plate. Spread a generous layer of frosting on top of that cake slice. Repeat layering and frosting until you have four cake layers on top of one another with a frosting layer in between each.
Spread a thin layer of frosting over the entire cake, this is called a crumb coat, and place in fridge for 10 minutes to set a bit. Remove from fridge and finish decorating cake as desired. This could include adding another layer of thicker frosting to the entire cake, doing some piping, or leaving as is if you want a minimal, “naked” cake. Add Pirouline cookies as decor. Serve immediately, or store in the fridge for up to 5 days. Just remember to take the cake out of the fridge a few hours ahead of time if you’re not serving the cake right away, giving it time to come to room temperature.