Preheat oven to 160ºC / 180ºC fan/Gas Mark 3.
Place butter and sugar into a bowl and beat until light, fluffy and pale in colour.
Add eggs and flour and combine all the ingredients together. Slowly add the food colour and mix to achieve the desired shade.
Pour cake mixture into the prepared cake tin and bake in the centre of the oven for 30-35 minutes until well risen and firm to touch.
Leave to cool in the tin for a few minutes then turn out onto a cooling rack. Leave to cool.
Repeat the process for the remaining colours.
Beat the the butter, sifted icing sugar and vanilla flavour together until smooth to make the buttercream.
Trim and level your cakes. Layer each colour using buttercream.
Coat the cake with the remaining buttercream.
Decorate and enjoy!
Tag @pmecake so we can see your amazing cakes!
To avoid a wonky cake, make sure your layers are neatly trimmed. For a straight top use a cake leveller and for the sides place a cake board slightly smaller than the cake and trim off the cake crust using a serrated knife!
Test bake your colours with a cupcake to help you decide on a shade of colour!