Preheat your oven to 350°F (175°C). Grease and flour a baking pan.
In a mixing bowl, cream the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition.
In another bowl, whisk together the flour and baking powder. Gradually add to the creamed mixture alternately with milk, beating well after each addition. Stir in the vanilla extract.
Pour the batter into the prepared pan. Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.
Cool in the pan for 10 minutes before removing to a wire rack to cool completely.