01 -
Toss the butter and marshmallows in a big pot, heating them slowly on medium heat. Keep mixing until it all turns into a smooth, gooey blend.
02 -
Pour in the puffed rice cereal and stir until every bit is wrapped in the creamy mixture.
03 -
Gently fold in the M&M's to sprinkle in some fun colors and extra sweetness.
04 -
Spread it all into a greased 9x13-inch pan. Let it cool completely, then cut it into squares when ready.