Spray a 9x9 pan lightly with cooking spray, set aside.

Melt butter over low heat in large saucepan on stove. When butter is melted, stir in marshmallows until melted. Remove from heat and stir in cereal until completely combined. Evenly distribute the marshmallow mixture into the prepared pan and press it into an even layer using a greased wooden spoon. Greased, clean hands work as well. Let stand at least 2 hours to cool.

Cut into desired shapes using cookie cutters.