Preheat the oven to 350°F (180°C) and grease a 9 x 5 inch loaf pan.
In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt.
In a large bowl, beat the butter and sugar together until light and fluffy. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.
Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk, and mix until just combined.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake for 55-60 minutes, or until a toothpick inserted into the center of the loaf comes out clean.
Cool the chocolate loaf in the pan for 10 minutes before removing it from the pan and placing it on a wire rack to cool completely. Serve and enjoy!