Preheat the oven to the appropriate temperature.

In a mixing bowl, cream together the unsalted butter and granulated sugar until light and fluffy.

Add the eggs one at a time, beating well after each addition.

In a separate bowl, combine the sifted flour, baking powder, and salt.

Gradually add the dry ingredients to the butter mixture, alternating with the milk, and mix until smooth.

Stir in the vanilla extract.

Pour the batter into prepared cake pans and bake for 30 minutes or until a toothpick comes out clean.

Allow cakes to cool before frosting.

For frosting, cream the unsalted butter and powdered sugar together.

Add the milk and vanilla extract to the frosting and mix until well combined.

Frost the cooled cakes as desired.