01 -
Preheat the oven to 350°F (175°C). Grease three 9-inch cake pans and line the bottoms with wax paper.
02 -
In the bowl of an electric mixer with a paddle attachment, whisk together the flour, sugar, cocoa, baking soda, baking powder, and salt.
03 -
In a separate bowl, mix the buttermilk, oil, eggs, vanilla extract, almond extract, and bourbon until well combined.
04 -
With the mixer on low speed, slowly add the wet ingredients to the dry ingredients. Add the hot coffee and mix until fully incorporated.
05 -
Divide the batter evenly among the prepared cake pans. Bake for 20-30 minutes or until a toothpick inserted in the center comes out clean.
06 -
Place egg whites and sugar in a heatproof bowl over a pot of simmering water. Whisk constantly until the sugar dissolves and the mixture reaches 160°F (71°C).
07 -
Transfer the bowl to a stand mixer fitted with the whisk attachment. Beat on medium-high speed for 5 minutes until stiff peaks form.
08 -
Reduce speed to medium and add butter one piece at a time, ensuring each piece is fully incorporated before adding the next.
09 -
Switch to the paddle attachment. Add the blackberry puree on low speed, then increase to medium speed and beat until the buttercream becomes firm and smooth.