For the cupcakes
Heat the oven to 180°C (160° fan) 350°F gas 4. Place paper cases in a 12-hole bun tin.
Beat all the cake ingredients in a mixing bowl until smooth and creamy.
Add more milk if the mixture is too stiff, to give a soft dropping consistency. Spoon into the paper cases and bake for 18-20 minutes until springy to the touch.
Cool for 5 minutes in the tins, then place on a wire rack to cool completely.
For the topping
Whisk the cream and icing sugar until thick. Spoon into a piping bag and pipe on top of the cakes. Sift cocoa powder over the top just before serving.