-Preheat oven to 350 degrees.
-Line the cupcake tins with paper liners.
-Sift flour, baking powder, salt, and baking soda together in a bowl.
-Beat butter on high for 30 seconds.
-Add sugar, vanilla, and Dr. Pepper to the butter …. beating until well combined.
-Add egg whites, and then eggs one at a time, beating well after each addition.
-Alternate adding the flour mixture and buttermilk to the butter mixture, beating on low speed until everything is mixed together.
-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.
-Bake at 350 degrees for 20-25 minutes or until an inserted cupcake comes out
-Allow cooling in the cupcake tine for 10 minutes.
-Remove the cupcakes from the cupcake tin and completely cool on a wire rack.
-Cream the butter and powder sugar until it looks light and creamy.
-If it doesn’t cream add 1 TBSP of the heavy whipping cream.
-Test to see if the frosting can form and hold a stiff peak.
-Add Dr. Pepper soda…. mix well.
-If not add more powder sugar 1/2 C at a time.
-Test to make sure that the frosting can make and hold a stiff peak.
-Add several drops of burgundy gel food coloring..mix well.
-Scoop the burgundy frosting into a pastry bag with a 13 inch round frosting tip…. twist the open end of the pastry bag to push the frosting to the tip….
-Frost cupcakes from the outside edge to the center of the cupcake.