Make cupcakes. Prepare batter following recipe directions. Bake and cool completely.
Decorate tops of cupcakes. Prepare buttercream and chocolate buttercream icing recipes, separately, following recipe directions. Tint portions of white buttercream icing orange and green. Use spatula and chocolate icing to ice tops of cupcakes smooth. Sprinkle with cookie crumbs. Chill until set, 15 minutes.
Make carrots. Use knife to cut out circle in center of cupcakes. Use tip 2A and orange icing to fill in center of cupcake and pipe carrot over chocolate icing. Use tip 352 and green icing to pipe pull-out stems on carrot tops.