Preheat the oven to 160^oC. Combine butter, sugar and vanilla essence in a bowl and beat with an electric mixer until light and creamy. Add the eggs, two at a time, beating well. Sift the flour and baking powder over the wet mixture and mix until combined.

Line two 12 hole 4 oz [1/2 cup] capacity muffin tins with patty cases. Spoon in the mixture until 3/4 full and bake for 35 minutes until cooked. Test with a skewer. Cool and decorate.