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 Key Lime Filling, stir together all ingredients in a medium bowl until blended. Chill 1 hour or until thick. Makes 2 cups. Fill each cupcake with cupcake with Key Lime Filling.
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.
To prepare whipped cream, beat whipping cream at high speed with an electric mixer until soft peaks form. Add vanilla and sugar, and beat until stiff peaks form. Store in refrigerator until ready to use. Makes 3 cups. Frost each cupcake with Fresh Whipped Cream. Top with graham cracker crumbs and lime rind.