Rainbow cake

INGREDIENTS

• 125g butter , softened, plus a little extra for greasing
• 225g plain flour
• 150g golden caster sugar
• 3 medium eggs (very important to use the correct size)
• 1 tsp baking powder
• pinch of salt
• 1 tsp vanilla extract
• edible food colouring - red, orange, yellow, green, blue and purple, plus optional pink (see below)
• 3 x 250g tubs cream cheese or mascarpone
• 350g icing sugar