1. Preheat your oven to 160C and grease 3 X 20cm tins. 
2. Beat the butter and sugar in a bowl until light a fluffy. Add the eggs one by one beating them in and combining well each time. You can do all this with a stand or electric whisk. 
3. Now add the dry ingredients and vanilla then fold through.
4. Add the milk to loosen the batter and then divide into three tins. Bake for 40-50mins until a knife comes out clean. 
5. Leave to cool before removing from the tin and then transfer to a wire rack to cool completely.
6. While they are cooling make the buttercream by beating all the ingredients together until you make a smooth paste. 
7. To assemble place onto a cake stand one of the bases and pipe buttercream in between each layer.
8. Finish the top layer with buttercream and sprinkles.

Serve and enjoy.