Retro Tinsel Christmas Tree Cookies

"A clever decorating technique means it’s never been easier to trim the tree, so you can give your sugar cookies the royal treatment—without making royal frosting. Instead, these cookies get their retro-fun and bakery-perfect look from a dip in a bowl of warmed Betty Crocker™ Rich & Creamy vanilla frosting. Tint the frosting with your favorite Christmas colors, pipe on a garland, add a shimmer and whatever other decorations you desire, just don’t forget to top your trees with a star—an M&M’s® candy work..."