Line a 12-section bun tray with paper cake cases. Beat all the cake ingredients together until light and creamy. Divide the mixture evenly among the cake cases. Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 18–20 minutes until risen and just firm to the touch. Transfer to a wire rack to cool.
Knead the white ready-to-roll icing on a surface lightly dusted with icing sugar until slightly softened. Roll out thickly and cut out star shapes using a small star-shaped biscuit cutter. Transfer to a baking sheet lined with nonstick baking paper and leave to harden while decorating the cakes.
Spread the icing roughly over the cakes and scatter with coconut. Gently press 2 stars into the top of each cake and leave to set.