Into a mixing bowl, add Mini Marshmallows (3 cup) and Salted Butter (2 1/2 tablespoon). Heat in the Panasonic Microwave Oven for 2 minutes, then stir together.
Return to the Panasonic Microwave Oven for 1 minute. Stir until smooth.
Add Rice Cereal (3 cup) and mix quickly.
Add Peanut Butter Chips (3/4 cup) and M&M's® Milk Chocolate Minis (3/4 cup). Stir to incorporate.
Transfer mixture to an 8x8-inch pan lined with parchment paper. Smooth out the top. Sprinkle over additional M&M's and peanut butter chips if desired, then press them in.
Fold in half. Press together. Let sit for 15 minutes.
Slice and serve! Cooking results may vary depending on microwave oven used.