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 4 parts, alternating with the milk, vanilla and peppermint extract. 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.