Dipped chocolate sandwich cookies with festive frosting

Chocolate sandwich cookie (unbleached enriched flour [wheat flour, niacin, reduced iron, thiamine mononitrate, riboflavin, folic acid], sugar, palm oil and/or canola oil, cocoa processed with alkali, high fructose corn syrup, leavening [baking soda and/or calcium phosphate], salt, soy lecithin, chocolate, artificial flavor), white chocolate (sugar, cocoa butter, whole milk powder, nonfat dry milk, soy lecithin, natural vanilla extract), dark chocolate (unsweetened chocolate, sugar, cocoa butter, soy lecithin [emulsifier], natural vanilla extract), sparkling sugar (sugar, carnauba wax), red color (medium chain triglycerides, red 40 lake, soy lecithin), orange color (medium chain triglycerides, yellow 6 lake, soy lecithin).