Preheat the oven to 350°F (175°C) and prepare cake pans.
Whisk flour, baking powder, and salt in a bowl.
Beat butter and sugar until fluffy; add eggs and vanilla.
Mix milk and sour cream in a separate bowl.
Alternate adding dry and wet ingredients to the creamed mixture.
Divide batter, bake for 28–32 minutes, then cool and frost.
