Preheat the oven to 325F and line a baking sheet with parchement paper then set aside.
In a large mixing bowl or a stand mixer bowl, cream the cold butter, granulated sugar, and brown sugar together until light and creamy.
Add in the egg, and vanilla extract, and mix until combined.
Sift in the flour, baking soda, and salt and mix just until the flour mixture disappears. Add in the M&M's, peanut butter chips, and chocolate chips and gently fold.
Using a large cookie scooper, scoop out 8 equally sized cookie dough balls, place them on a baking sheet, and gently press down to about 1 inch in thickness. Bake in the preheated oven for 12-13 minutes.
As soon as you pull out the cookies from the oven, top with a few extra chocolate chips, Peanut butter chips, and M&M's, and let the cookie rest on the baking sheet for 20 minutes or until fully cooled down to set before enjoying them.