Add peppermint extract and sour cream to cake batter. Add pudding mix aftger it is well mixed, scrapiing sides. Add 1/2 c crushed candycanes at the last just until incorporated. Scoop into papered cupcake pans, 2/3 full. Bake at 350 for about 12 min or until toothpick comes out clean.
Place canned frosting in mixer, adding powdered sugar to thicken it slightly, scraping sides. Afix star shaped tip to piping bag. Run a streak of the red frosting or gel frosting up one side of the piping bag then fill with white frosting. Top your cupcakes. Sprinkle some of remaining crushed candies over top.