Preheat the oven to 180 C / Gas 4. Line a 12-hole muffin tin with paper cases.
In a bowl, cream together the butter and sugar until light and fluffy. Add the eggs, one at a time and beat until pale and creamy then add the vanilla.
Finally sieve the all the flour into the mixture and fold with a wooden spoon. This will allow the mixture to maintain the air to get light and fluffy cupcakes. Spoon the mixture into the prepared paper cases, filling only to half way to allow for a good rise.
Bake in the preheated oven to 18 minutes, or until rise and golden brown and a skewer inserted into the centre comes out clean. Remove from the oven and allow the cupcakes to cool for 1 hour.
For the buttercream icing:
Cream the butter and icing sugar to create the butter icing. With a piping bag and a piping head, pipe the icing on to the cupcakes in any pattern you desire. You can decorate with anything, I used grated chocolate.