Preheat your oven to 350°F (175°C). Grease two 9-inch round cake pans and line the bottoms with parchment paper.

In a mixing bowl, combine the flour, cocoa powder, baking powder, baking soda, and salt. Whisk until thoroughly mixed.

In another large bowl, beat the softened butter and sugar together until light and fluffy. Incorporate the eggs one at a time, followed by the vanilla extract.

Gradually add the dry mixture to the butter and sugar blend, alternating with the buttermilk, until just combined.

Divide the batter between the two pans, smoothing the tops evenly with a spatula.

Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cakes to cool in their pans for about 10 minutes before inverting onto wire racks to cool completely.