Color the frosting red, put in a piping bag, and pipe swirls of frosting on each cupcake upwards to a point so it looks like a hat and sprinkle red sugar all over.

Place marshmallows all around the bottom edge of each frosting hat so it looks like the white part of Santa’s hat. Take 6 marshmallows and dampen with a bit with water, and sprinkle the white glitter all over them. Stick one on the top of each hat.