Preheat the oven to 180°C / Gas mark 4
Sift together the flour, baking powder and salt in a bowl.
Put the butter and sugar in a mixing bowl and beat until pale and fluffy. Stop occasionally to scrape down the side of the bowl with a rubber spatula. Add the vanilla and then start adding in the eggs, one at a time, beating well after each addition.
Slowly add the sifted dry ingredients and beat on a low speed until combined.
Divide the mixture between the muffin cases. Bake in the preheated oven for 20-25 minutes or until well risen and a skewer inserted into the middle comes out clean. Remove from oven and allow to cool completely before decorating.