Line 9" square pan with parchment paper. Set aside.
In a small sauce pan, melt peanut butter and honey. Add to large bowl with Cheerios and puffed rice cereals and stir until combined. Add chocolate chips (if desired) and gently stir one more time.
Spread cereal mixture evenly into pan, pressing down slightly to make bars flat and even on top. Don't forget about the corner. Stick in the freezer for 20 minutes before cutting.
Storage: You can store these at room temperature, but the texture gets a bit sticky, so I prefer storing these in the refrigerator or freezer when not eating. They only require sitting out for a few minutes from the freezer before eating.