Preheat oven to 350 degrees F.
Line 2 (1/2 cup-12 capacity) muffin tins with cupcake papers.
In a small bowl, combine the flours. Set aside.
In a large bowl, on the medium speed of an electric mixer, cream the butter until smooth. Add the sugar gradually and beat until fluffy, about 3 minutes. Add the eggs, 1 at a time, beating well after each addition. Add the dry ingredients in 3 parts, alternating with the milk and vanilla. With each addition, beat until the ingredients are incorporated but do not over beat. Using a rubber spatula, scrape down the batter in the bowl to make sure the ingredients are well blended. Carefully spoon the batter into the cupcake liners, filling them about 3/4 full. Bake for 20 to 25 minutes, or until a cake tester inserted into the center of the cupcake comes out clean.
Cool the cupcakes in tins for 15 minutes. Remove from the tins and cool completely on a wire rack before icing.
Place the butter in a large mixing bowl. Add 4 cups of the sugar and then the milk and vanilla. On the medium speed of an electric mixer, beat until smooth and creamy, about 3 to 5 minutes. Gradually add the remaining sugar, 1 cup at a time, beating well after each addition (about 2 minutes), until the icing is thick enough to be of good spreading consistency. You may not need to add all of the sugar. If desired, add a few drops of food coloring and mix thoroughly. (Use and store the icing at room temperature because icing will set if chilled.) Icing can be stored in an airtight container for up to 3 days.
The vanilla buttercream we use at the bakery is technically not a buttercream but actually an old-fashioned confectioners' sugar and butter frosting. Be sure to beat the icing for the amount of time called for in the recipe to achieve the desired creamy texture.
Recipe courtesy Allysa Torey, More From Magnolia: Recipes from the World-Famous Bakery and Allysa Torey's Home Kitchen, Simon and Schuster, 2004