add the butter & marshmallows in a bowl and melt them together. This can be done in the microwave or on the stove top.
add green food coloring and stir. add as needed until you reach desired shade
add in Rice Krispies and mix thoroughly. add more food coloring if cereal is not green enough.
spread the mixture into a greased pan with a greased spatula.
allow mixture to cool (about 30 minutes)
cut half of pan into 2x2 inch squares
use heart shaped cookie cutter to cut the other half
use red decorative gel to draw hearts (solid and outlines)
serve & enjoy!