Pull out about ½ cup of frosting and dye black for Santa’s belt. Adding some cocoa powder to the frosting first will keep you from having to add so much food coloring.
Dye the remaining frosting red.
Either spread the red frosting over the cupcakes or pipe with a round piping tip. .
Using a small flat tip, pipe a black belt about ⅓ of the way up the cupcake.
Roll out the fondant (or yellow candy) and cut into small rectangles. About ½ by ¼″ is a decent size, but you can just eyeball the size that looks good with your belt. Place in the center of the black stripe.
Add two mini chocolate for buttons above the belt.