Preheat your oven to 350°F (175°C). Grease and flour your cake pans.
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.
Mix in the vanilla extract.
In another bowl, whisk together the flour and baking powder. Add to the creamed mixture alternately with the milk, beating well after each addition.
Pour the batter into the prepared pans and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
Let the cakes cool in the pans for 10 minutes, then remove to wire racks to cool completely.
For the frosting, beat the butter until creamy. Gradually add the powdered sugar, beating until smooth. Mix in the vanilla and enough milk to achieve a spreadable consistency.
Frost the cooled cake as desired.