• In a large saucepan over medium heat, add butter and melt it
• Once the butter is melted add the marshmallows
• Reduce heat to low and stir marshmallows until they are melted
• Remove from heat
• Add some food coloring and stir in - Add more if you want a darker color
• Pour rice crisp cereal into a large mixing bowl and fold in the colored marshmallow
• Line a baking dish with parchment paper
• Scoop the rice krispies cereal into the baking dish and spread out
• Let it cool off enough for the marshmallows to harden a little bit, so when you lift it up out of the pan it won't fall apart
• Once the marshmallows have set up a little bit, lift the parchment paper up and out of the baking dish

Decorating

• Spread some of the chocolate frosting onto the top part of the rectangle, pulling some down into jagged edges for Frank's bangs
• Sprinkle chocolate sprinkles onto the frosting
• Use kitchen shears to cut the tips off of a regular sized marshmallow
• Place those tips onto the rectangle for the eyes
• Add M&Ms to the center of the marshmallows and black gel for the pupils
• Scoop the rest of the chocolate frosting into a piping bag that has been set up with a writing tip
• Draw stitches for a mouth and eyebrows
• You can also add some more stitches to Frank's forehead
• Add a couple of mini marshmallows on the neck portion for Frank's bolts
• When the frosting has had time to dry and harden, you can transfer Frank onto a tray and cut the large rice krispies treat into smaller rectangles