1. Preheat the oven to 180°C (160°C Fan, Gas Mark 4). Arrange the Cupcake Cases spaced apart on a baking tray.
2. Put the margarine, sugar, Vanilla Extract and egg in a bowl. Sift the flour on top and then beat all the ingredients together using an electric whisk until well blended.
3. Divide the mixture between the Cupcake Cases. Smooth the tops and bake in the oven for 20-22 minutes until risen, lightly golden and just firm to the touch. Transfer to a wire rack to cool.
4. To decorate, using a small spoon, scoop out a piece of sponge from the centre of each cake and fill with Rainbow Popping Candy. Replace the scooped out cake on top, trimming if necessary, to snugly fit the top of the cake again.
5. Follow the directions on the can of Easy Swirl. Starting in the middle of a cake, pipe the icing round in an anti-clockwise direction to cover the top of the cake then continue piping round to form a swirl on top.
6. Just before serving, sprinkle the cakes with a few more pieces of Rainbow Popping Candy. Your cakes are now ready to serve and enjoy!