Preheat oven to 350 degrees. Line two baking sheets with silpat/silicone liners or parchment paper.

Stir together peanut butter, sugars, egg, and baking soda. Stir in 1/2 cup M&Ms.

Scoop cookies onto cookie sheets. I used a 2” cookie scoop for this step. Lightly wet the back of a fork with water and gently press each cookie down slightly with a criss-cross pattern. (Re-wet your fork after every few cookies.) Press remaining M&Ms on top of the cookies.

Bake for about 8 minutes or until they start to brown. Cool before removing from cookies sheets. Know that these cookies can be crumbly, so be careful when packaging them.