Add the butter & marshmallows in a bowl and melt them together. This can be done in the microwave or on the stove top.
Add in food coloring and stir. Add food coloring until the desired shade is reached
add in Rice Krispies and mix thoroughly
Spread the mixture into a greased pan with a greased spatula.
Allow mixture to cool (about 30 minutes), cut into squares
spread icing on each square in either a diagonal pattern or completely
add sprinkles to top
serve and enjoy!