Step 1: Preheat Your Oven. Begin by preheating your oven to 350°F (175°C). This ensures that your cookies will bake evenly.
Step 2: Prepare Baking Sheets. Line your baking sheets with parchment paper to prevent sticking and make cleanup a breeze.
Step 3: Cream the Butter and Peanut Butter. In a large mixing bowl, combine softened unsalted butter and creamy peanut butter. Using an electric mixer, beat them together until the mixture is smooth and creamy.
Step 4: Add Sugars and Vanilla. Add the light brown sugar, granulated sugar, and vanilla extract to the butter mixture. Beat until well combined and fluffy.
Step 5: Incorporate the Egg and Milk. Crack in the large egg and pour in the milk. Mix until everything is fully combined.
Step 6: Combine Dry Ingredients. In a separate bowl, whisk together the all-purpose flour, baking soda, and salt. Gradually add this dry mixture to the wet ingredients, mixing until just combined.
Step 7: Fold in the M&Ms. Gently fold in the M&Ms, ensuring they are evenly distributed throughout the cookie dough.
Step 8: Scoop the Dough. Using a cookie scoop or tablespoon, scoop out portions of dough and place them onto the prepared baking sheets, leaving enough space between each cookie to allow for spreading.
Step 9: Bake the Cookies. Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden. The centers may look slightly underbaked, but they will firm up as they cool.
Step 10: Cool and Enjoy. Once baked, remove the cookies from the oven and let them sit on the baking sheet for about 5 minutes before transferring them to a cooling rack. Allow them to cool completely before indulging.
