Preheat oven to 350 degrees. Line a 9 x 13-inch baking dish with foil leaving an overhang to make removing the cookies easier. Spray foil generously with non-stick spray.

In a large bowl, whisk together flour baking soda, and salt; set aside.

In the bowl of a stand mixer, beat butter and sugars together until light and fluffy. Add eggs and vanilla, beat until combined.

Lower the speed of the mixer and gradually add flour mixture, beat until just combined.

Stir in 1 cup M&M’s, mini chocolate chips, and white chocolate chips.

Transfer the cookie dough to the prepared baking dish. Press the remaining M&M’s on top of the cookie dough.

Bake 30-35 minutes in the lower third of the oven to prevent over-browning.

Cool completely and cut into squares.