Preheat the oven to 160ºC (fan assisted, 180°C non fan) and line three 8 inch loose bottomed cake tins

Add the margarine and sugar to your mixer and beat until light and fluffy

Crack in the eggs and mix again

Add the flour, baking powder, bicarbonate of soda and salt and mix briefly

Whisk the yogurt, milk and vanilla extract together in a jug before pouring into the cake mix. Mix until completely combined

Gently fold in the sprinkles being careful not to overmix because the sprinkles will bleed their colour

Pour the mix evenly into the three prepared cake tins

Bake in the oven for 25-30 minutes . If the cakes start to become too brown, cover them loosely with foil. The cake is done when a cocktail stick comes out clean

Leave to cool in the tins for 20 minutes before turning out and allowing to cool completely on a wire rack

When the cakes are completely cooled, make the buttercream

Beat the butter in your mixer until soft, you don't want any lumps of butter left

Add in the icing sugar and mix. Add in enough milk to get a a smooth consistency

If you want to make sure your cake is as flat as possible, level off two of the cakes. Leave your flattest cake for the top layer

Lay one of the cakes upside down on your cake board or presentation plate. Pipe or spread a layer of buttercream evenly over the cake

Lay the next layer of cake upside down on top of the icing and spread the buttercream out again

Lay the final layer layer the right side up on top of the other cakes. Spread a layer of the buttercream on the final layer and pipe a few decorations on. Finish with a few sprinkles