4 oz 100g butter/Margarine.
8 oz 225g icing sugar sifted.
1 tsp vanilla essence.
1. Beat the butter/margarine using a wooden spoon until soft.
2. Add the essence, mix icing sugar a little at a time until all is mixed in.
3. Using a pallet knife spread the mixture over the middle(filling) top of your cake, to stop it dragging over your cake keep dipping the knife in a cup of freshly boiled water.
For different flavour add 1-2 tbsp cocoa powder, or food flavouring. Change the colour ad 1-2 tsp food colouring.