Line 2 cookie sheets with parchment paper. With a hand mixer, beat frosting, powdered sugar, and vanilla in large bowl until smooth. Using a tablespoon measuring spoon or a 1-ounce cookie scoop, form into balls and place on cookie sheet. Dust truffles with cocoa powder. Cover and refrigerate truffles until ready to serve.
Recipe courtesy Sandra Lee Semi-Homemade Desserts, Miramax Books, 2003.