Preheat oven to 350F (175C) and line several baking sheets with parchment paper. Set aside.

In a large mixing bowl, use an electric mixer (or stand mixer) to cream butter and sugar together until light and fluffy.

Add eggs, vanilla extract, and peppermint extract and stir until thoroughly combined.

In a separate, medium-sized mixing bowl, whisk together flour, cornstarch, baking powder, baking soda, and salt.

Gradually stir dry ingredients into wet until completely combined.

Add food coloring (if using) and stir until fully combined.

Add M&Ms (I add slightly over a cup/about 240 grams at this point and reserve the rest for topping the cookies, but you can stir them all into the batter if you prefer) and use a spatula until evenly distributed through batter.

Scoop by 1 ½ Tablespoon-sized scoop and drop onto baking sheet, spacing cookies at least 2” (5cm) apart.

Bake in center rack of 350F (175C) preheated oven for 8-10 minutes. Remove from oven and immediately top with reserved M&Ms (if you reserved any). Allow cookies to cool completely on baking sheet before enjoying.