Preheat oven to 190°C/Gas 5.
Line a cupcake tin with paper cases.
In a large a mixing bowl, beat the butter and sugar together until smooth, light and fluffy.
Add the eggs. Beat.
Fold in the gluten free flour.
Add up to 2 tbsp milk if required.
Put spoonfuls of the mixture into base of paper cases.
Place a piece of chocolate or drop teaspoons of chocolate spread on top, then top with another spoonful of mixture.
Bake for 20-25 minutes until risen and golden brown. Cool on a wire tray.
Beat the butter, icing sugar and cocoa powder together until smooth.
Once the cupcakes are cool, pipe or spread the buttercream on top and decorate as desired.