Grease a baking sheet or pan by generously rubbing a stick of butter across it or spraying with nonstick cooking spray. Set aside.
In a large pot, melt the butter over low heat.
Add marshmallows and stir constantly until completely melted.
Turn off the heat. Once marshmallow mixture has melted, add vanilla and fold in with a spatula. Add food coloring and stir until marshmallow mix is green.
Fold in rice cereal.
Place mixture into your buttered baking sheet and spread evenly. Lay a piece of parchment across the mixture and use a rolling pin to press mixture into an even width.
Using your cookie cutters, cut out your desired shapes (and enjoy the scraps!)
Place on parchment paper.
Decorate with gold sprinkles or dip in melted candy melts if desired.