Preheat the oven to 165°C – 330°F and line muffin trays with papers.

Combine the flour, cocoa, baking powder and salt together in a bowl and set aside.

Then cream the butter, vanilla and brown sugar until pale and fluffy.

Add the eggs, one at a time, beating until well incorporated. Remember to scrape down the sides of the bowl as needed.

Add the flour and cocoa powder mixture in three batches, alternating it with two additions of buttermilk (or yogurt) and milk. Beat until well combined.

Put the batter into the lined muffin tray cups, filling each to about half.

Bake for about 25 minutes or until cooked through.

When cooked, let them cool down in the tray for 10 minutes, then put them on a wire rack to cool down completely.

Beat the softened butter with an electric mixer fitted with a paddle attachment for a few minutes and then slowly incorporate the icing sugar, cocoa powder, milk and vanilla extract. Mix well.

Put the chocolate buttercream in a piping bag and decorate the chocolate cupcakes with it.