Preheat oven to 350 degrees. Line cupcake pan with paper liners.
Sift flour, baking powder, salt, and baking soda together in a bowl.
Beat butter on high for 30 seconds.
Add sugar and vanilla extract to the butter until well combined.
Add egg whites, one at a time, mixing after each.
Add eggs, one at a time, mixing after each.
Add 1/3 C flour mixture to the wet mixture followed by adding 1/3 C of the buttermilk; add 1/3 C flour mixture again then add 1/3 C buttermilk mix on low speed, add 1/3 C of flour and add the rest of 1/3 C of buttermilk mix in low speed until thoroughly blended.
Divide the batter into three bowls.... add red gel food coloring to one.... add blue gel food coloring to the second and the third remains white. Stir well.
Begin by spooning in some of the red batter then the blue... using a spoon twirl the two colors together.
Place your star in the center and build the cupcake.... continue with the blue batter then the red batter.... using a spoon twirl the two colors together. -The batter should reach 2/3rds of the top of the lined cupcake holders.
Bake at 350 degrees for 20-25 minutes or until an inserted toothpick comes out clean.-
-Remove to a wire rack until fully cooled