1. Preheat the oven to 180C. Line a muffin tin with flouncy cases. In a bowl, sift the flour, cocoa powder, bicarbonate of soda and baking powder.

2. Add the sugar, butter and sour cream. Mix well until the mixture looks like breadcrumbs.

3. Stir together the vanilla and eggs, add bit by bit to the flour mixture, slowly so it doesn’t curdle.  Stir in the colouring until a lovely shade of blue.

4. Pour the mixture into the awaiting cases two-thirds full. Bake for 20 minutes. Leave to cool.

5. To make the frosting, beat the butter and cream cheese until fluffy. Slowly beat in the icing sugar so you don’t cover yourself in the sugar and inhale the stuff. Add the vanilla extract and beat until smooth.

6. Spoon the frosting into a piping bag fixed with a plain nozzle and pipe the frosting on top of the cooled cakes. Sprinkle with edible glitter or sprinkles.