This is my fail-safe recipe for chocolate cupcakes made with cocoa powder. Use whatever type of chocolate you prefer for the chocolate buttercream icing: dark, milk, or even flavoured chocolate such as mint or orange work well.
Preheat the oven to 200 degrees C / Gas mark 6. Line 2 - 12 hole bun trays with colourful paper cases.
Sift the cocoa into a large bowl; add 4 tablespoons of boiling water and mix into a thick chocolate syrup, adding more water if you needed. Add the softened butter, sugar, self-raising flour, baking powder and eggs. Mix with electric beaters until smooth and evenly mixed.
Spoon teaspoons of the mixture into the paper cases, filling them 3/4 full. Bake for 10 minutes, or until the sponge mixture has risen and the cupcakes spring back when you touch them. Remove from the oven; cool on a wire rack.
To make the chocolate icing: Mix the melted chocolate and softened butter in a large bowl; sift in the icing sugar, beating with a spoon or an electric beater until smooth. Spoon into a piping bag with a number 5 star nozzle. Pipe buttercream icing evenly on top of each cupcake. Decorate with chocolate sprinkles or however you like.