How can I put icing (like sugar cookie icing) on the outside of an ice cream cone to make it look like a Christmas tree with popcorn decorations?
I would say that you need to dip the cone in chocolate first and let it dry. You can use a white chocolate to dip them in and add a bit of food coloring if you want. Let them dry and cool. Now use a piping gun to make piping icing to put on the ouside of the cone. Finish decorating your cones the way you want.
Paint on white frosting that you have dyed green, then put on the popcorn.
You can use candy melts, they carry it in green and other colors. You melt and dip in.Done,you can also use white candy melts for snow!