01 -
Preheat oven to 350°F (180°C). Line baking sheets with parchment paper or silicone baking mats. Set aside.
02 -
In a medium-sized bowl, combine the flour, cornstarch, baking soda, baking powder, and salt. Set aside.
03 -
In a large mixer bowl, cream the butter and sugars together on medium speed until light and fluffy, about 2-3 minutes.
04 -
Add the eggs one at a time, mixing until well combined after each addition. Then mix in the vanilla extract until well combined.
05 -
Gradually add the dry ingredients to the wet mixture and mix on low speed until mostly combined. Avoid overmixing.
06 -
Using a silicone spatula, fold in the M&Ms and chocolate chips until evenly distributed. The cookie dough will be thick.
07 -
Form dough balls of 4 tablespoons (68g) each and place them on the prepared baking sheet, spacing them 2-3 inches apart. Shape the dough balls to be round.
08 -
Bake cookies for 8-10 minutes. Remove them just before the edges turn golden and the centers look soft. Avoid overbaking.
09 -
Allow cookies to cool on the baking sheets for 4-5 minutes before transferring them to a wire rack to cool completely.