Place half the marshmallows and half the butter in a large, microwave safe mixing bowl. Be sure to slice the butter into smaller pieces before adding it to the bowl.
Place the other half of the marshmallows and butter in a second bowl.
One at a time, add the bowls to the microwave and cook for 1.5 minutes on high, or until the marshmallows no longer have lumps and all the butter has melted. Do this for both bowls.
Mix vigorously to ensure the marshmallows and butter are fully combined.
Add the red dye to one bowl and the blue dye to the other bowl. Mix each bowl until no color streaks appear.
Add half the cereal to one bowl and the other half to the other bowl.
Fold the ingredients of each bowl until the cereal is fully covered by the marshmallow mixture.
Spray each pan with cooking spray then pour the red mixture onto one pan and the blue mixture onto the other pan.
Spread and press down each color until even and covering the entire pan. Spray some cooking spray on your hands to make it easier for this step, if desired.
Cover the top of each pan with patriotic sprinkles, then leave both pans to sit for about 30 minutes or until fully set.
Once set, use your cookie cutter to cut out as many stars as you can from both the blue and red rice krispie treats.
Place the frosting in a frosting bag with the tip and add frosting to the unsprinkled side of half the stars, being careful to not go all the way up the skinny portion of the star’s tips.
Place the unfrosted stars on top of the frosted ones, with the sprinkle side facing away from the frosting. You want the sprinkle sides to be visible on both sides.
Serve and enjoy!