Prepare a sheet pan with parchment paper and set aside.
Chop candy bars into bite sized or smaller pieces.
In a medium bowl whisk together the flour, baking powder, baking soda and salt.
In a large bowl cream the butter and brown sugar together using a hand mixer on medium-high speed for about 3 minutes until light and fluffy.
Next add the eggs, egg yolk and vanilla and mix on medium low speed until combined.
Gradually add in the dry ingredient mixture on low speed and mix until combined.
Using a silicone spatula, fold in the chopped candy.
Scoop cookie dough with a medium cookie scoop onto the parchement-lined baking sheet. Add more M&M's to the top of the cookie dough balls.
Bake cookies for about 10 minutes or until lightly golden. Transfer to a cooling rack to cool after 5 minutes of resting on the baking sheet.
Notes
expert tips
These cookies are so fun to make with the kids! They will love unwrapping all the chocolates and mixing all the candy into the batter.
These cookies are best the day they are made but can be stored for 3-4 days in an air-tight container on the kitchen counter.
I love making the cookie dough balls and flash freeze them on a baking sheet and then storing them in the freezer in freezer bags to bake fresh when a craving strikes or as a quick treat for unexpected guests!
Customize your cookies with your favorite treats! I love candy-coated chocolates for color and crunch. I also like to use a candy bar that has some caramel that melts into the cookie. Potato chips or pretzels are also fun additions if you like the salty-sweet combo!