Preheat the oven to 190°C (170°C Fan, Gas Mark 5). Line a cupcake tin with 12 Cupcake Cases.

Beat the margarine with the sugar until light in texture.

Gradually whisk in the eggs and Madagascan Vanilla Extract.

Sift in the flour, cocoa powder and Baking Powder. Using a metal spoon, fold the dry ingredients into the mixture.

Spoon the mixture into the Cupcake Cases and bake for 20-22 minutes until risen and just firm to the touch. Transfer to a wire rack to cool.

For the icing, place the butter into a bowl and beat until soft. Gradually sift and beat in the icing sugar and cocoa powder to make a smooth buttercream. Add a little milk if the buttercream is too thick.

Fit a piping bag with a 1cm closed star nozzle then fill with buttercream and pipe onto the cupcakes. Place a Heart Marshmallow onto each cupcake to finish.