Heat oven to 350 degrees. In a large bowl, stir butter, peanut butter, and egg until blended. Stir in cookie mix until soft dough forms. I had to use my hands to get this blended together! Stir in M&Ms and Rice Chex, breaking cereal apart as you mix. Again, especially at this point I had to really use my hands and squeeze the dough together. There are a lot of chocolate chips and M&Ms!
Abigail helping measure.
Drop dough by rounded tablespoons onto an ungreased cookie sheet. Bake for 11 minutes or until edges are slightly golden brown. Cool for 2 minutes and then remove from cookie sheets and cool on wire rack. Enjoy!!