Preheat the Oven: Preheat your oven to 350°F (175°C). Line baking sheet with parchment paper.
Mix the Dry Ingredients: In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
Cream Butter and Sugars: In a large bowl, use a hand mixer or stand mixer to beat the softened butter, granulated sugar together until light and fluffy .
Add Egg and Vanilla: Beat in the egg and vanilla extract until well combined.
Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the wet mixture, mixing on low speed until fully combined. Avoid over mixing.
Fold in M&M’s: Use a spatula to fold in 1 cup of M&M’s and optional chocolate chips.
Shape the Cookies: Scoop the dough into 1.5-inch balls (about 1 tablespoon) and place them on the baking sheet, spaced about 2 inches apart. Press a few extra M&M’s onto the tops for a colorful finish.
Bake:Bake the cookies for 10-12 minutes, until the edges are lightly golden, and the centers still look slightly underdone. This ensures soft, chewy cookies.
Cool:Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.