Preheat your oven to 350°F (175°C). Grease two round cake pans and line them with parchment paper.

In a large bowl, whisk together flour, cocoa powder, baking powder, and sugar until combined.

In another bowl, beat eggs, buttermilk, vegetable oil, and vanilla until smooth. Gradually stir this mixture into the dry ingredients until just combined.

Divide batter evenly between prepared pans and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.

Allow cakes to cool for about ten minutes before transferring to wire racks to cool completely.

Beat softened butter and cocoa powder together before gradually adding powdered sugar and cream until creamy.

Frost cooled cake layers generously.