Combine dry ingredients in large mixing bowl.  Add butter, milk, and vanilla to the dry.  Stir until just mixed then mix at medium speed for about 4 minutes. Scrape bowl. Add eggs one at a time and mix on low speed for 30 seconds after each egg.  Once all eggs are in the batter, mix at medium speed for 1 minute.  Batter will be thick and fluffy. Preheat oven to 350°F.  Spoon batter into cupcake liners until 1/2 full. Bake your for 20 minutes or until a cake tester, or toothpick, inserted into the center of the cupcakes comes out clean. Cool completely in the cupcake pans. Store in an airtight container.