To prepare White Cake, Preheat oven to 350 degrees. Beat butter and shortening at medium speed with an electric mixer until creamy; gradually add sugar, beating well. Add eggs, 1 at a time, beating until blended after each addition.
Combine flour, baking powder, and salt; add to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed until blended after each addition. Stir in extracts.
Place paper baking cups in 2 (12-cup) muffin pans, and coat with cooking spray; spoon batter into cups, filling two-thirds full.
Bake for 12 to 15 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on wire racks 10 minutes; remove from pans to wire racks, and cool completely.
To prepare frosting, beat cream cheese, butter, and peppermint extract at medium speed with an electric mixer until creamy. Gradually add powdered sugar and salt, beating at low speed until blended. Beat at high speed 2 minutes or until creamy. Makes 6 cups.
To fill cupcakes, insert the end of a wooden spoon or dowel into the center of the cupcake to make a hole. Fill a zip-top plastic freezer bag with filling or frosting. Use scissors or kitchen shears to snip about 1/4 inch from one corner of the bag; insert bag into the hole in the cupcake. Squeeze gently until filling comes to the top of each cupcake.
Frost each cupcake.