Preheat the oven to 180 degrees celsius (gas mark 4). Grease and flour a 23cm tin or line a bun tray with paper cases.
In a medium bowl, cream together the sugar and butter. Beat in the eggs, one at a time, then stir in the vanilla extract. Combine flour and baking powder, add to the creamed mixture and mix well. Finally stir in the milk until the mixture is smooth. Pour or spoon mixture into the prepared tin or bun cases.
Bake for 30-40 minutes in the preheated oven. For fairy cakes, bake for 20-25 minutes. Cake is done when it springs back to the touch.