In a mixing bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In another bowl, whisk together the flour, baking powder, and salt. Gradually add to the creamed mixture alternately with milk, beating well after each addition.
Pour the batter into a greased baking tray and bake for 30 minutes or until a toothpick inserted into the center comes out clean.
Let cool completely before decorating as desired for Halloween.