How to Make It
Preheat the oven to 375° and position 2 racks in the upper and lower third of the oven. In a large bowl, using a wooden spoon, beat the butter until creamy. Add the brown and granulated sugars and beat until smooth. Add the eggs and vanilla and beat until smooth. In a small bowl, whisk the flour with the baking soda and salt. Add the dry ingredients to the large bowl and stir until combined. Stir in the white and semisweet chocolate chips.
Using a 1 1/2-inch ice cream scoop, scoop 3-tablespoon mounds of the cookie batter onto 3 ungreased baking sheets, about 2 inches apart. Using your hands, roll the dough mounds into balls. Insert the pretzel sticks into the dough balls and fill the empty spaces with M&M's Minis. Bake 2 sheets of the cookies until they are lightly browned by still soft in the middle, about 15 minutes, shifting the baking sheets from top to bottom and front to back halfway through. Let the cookies cool on the pans for 10 minutes, then transfer to wire racks to cool completely. Repeat with the remaining baking sheet, rotating the sheet halfway through baking. Serve warm or cooled.