Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and line a cupcake tin with cupcake cases
To make the sponge, mix together the butter and sugar, ideally using an electric mixer
Add the eggs and vanila extract and whisk well
Then whisk in the self raising flour gently
Divide the mixture equally into six bowls
Colour each bowl with the food colouring so you have bowls of red, yellow, orange, green, bue and purple cupcake batter
Divide each colour of batter one at a time between the cupcake cases
Bake them for 20-25 minutes or until a skewer inserted in the centre of the cupcakes comes out clean. Leave to cool completely on a cooling rack
Whip up the double cream with the icing sugar and vanilla until thick, put into a piping bag and pipe swirls onto each cupcake, or dollop on with a spoon
Decorate with marshmallows and gold sprinkles
Serve immediately. Store leftovers in the fridge and eat within 2 days