Preheat oven to 350 degrees F. Line a baking sheet with parchment paper or a silicone baking mat; set aside.

In a medium bowl, combine flour, baking soda and salt.

In the bowl of an electric mixer fitted with the paddle attachment, beat butter, shortening and sugars on medium-high until light and fluffy, about 2-3 minutes. Beat in vanilla until well combined. Beat in eggs, one at a time, until well combined. Gradually add flour mixture to sugar mixture at low speed, beating just until incorporated. Gently fold in M&M’s.

Drop tablespoons of batter onto prepared baking sheet. Place into oven and bake until edges are golden brown but center is still moist, about 9-10 minutes.

Remove from oven and cool on a wire rack.