Preheat the oven to 350F. Line a baking sheet or cooking sheet with parchment paper or silpat pad. Set aside.
Add cake mix, eggs, and oil to a large mixing bowl. Blend well with a whisk or an electric mixer, just until blended. Do not over mix.
Fold in half of the candy using a spoon or spatula.
Using a spoon or ice cream scoop, form tablespoon-size cookie dough balls and place them onto a prepared cookie sheet. Top each cookie dough ball with additional M&Ms. See my notes below about other topping ideas :)
Bake for 10-12 minutes. Remove from the oven. Let them cool for about 4-5 minutes, then transfer to a cooling rack.
Notes
Make sure to space the cookie dough apart at least 2 inches since they will spread out while baking.These cooking may look undercooked when you remove them from the oven, but after they have cooled off, they are just perfect - light and fluffy!This recipe works well with any flavor cake mix. There are lots of different add-ins and topping ideas such as white chocolate chips, milk chocolate chips, sprinkles, or powdered sugar.Store baked and cooled cookies on your countertop in an airtight container for 3-4 days.