First Step: PREPARE THE COOKIE DOUGH

1. Cream the Butter and Peanut Butter: Begin by creaming the softened butter and peanut butter together in a large mixing bowl using an electric mixer or stand mixer. Beat them until the mixture is light and fluffy, about 2-3 minutes.
2. Add the Sugars: Add the granulated sugar and brown sugar to the butter and peanut butter mixture. Continue to mix until the sugars are fully incorporated and the mixture is smooth.
3. Add the Eggs and Vanilla: Add the eggs, one at a time, mixing well after each addition. Then add the vanilla extract and continue to mix until the dough is well combined.
4. Add the Dry Ingredients: In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Be careful not to overmix, as this can lead to tough cookies.
5. Stir in the Mix-ins: Gently fold in the oats, chocolate chips, M&M’s, and any other add-ins like chopped nuts or sprinkles. Use a spatula or wooden spoon to mix everything together until the dough is evenly distributed.

Second Step: CHILL THE COOKIE DOUGH

1. Chill the Dough: Cover the cookie dough with plastic wrap or place it in an airtight container, then refrigerate it for at least 1 hour. Chilling the dough helps the cookies keep their shape and prevents them from spreading too much while baking.

Third Step: SHAPE AND BAKE THE COOKIES

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone baking mats to prevent the cookies from sticking.
2. Shape the Cookies: Scoop tablespoon-sized portions of cookie dough and roll them into balls. Place them onto the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
3. Bake the Cookies: Bake the cookies for 8-10 minutes or until the edges are golden brown, but the centers are still soft. The cookies will continue to cook slightly after being removed from the oven, so don’t overbake them.
4. Cool the Cookies: Allow the cookies to cool on the baking sheets for a few minutes before transferring them to wire racks to cool completely.

Final Step: GARNISH AND SERVE

1. Add Extra M&M’s (optional): If desired, press a few extra M&M’s into the top of the cookies just before baking to make them look even more festive.
2. Garnish with Sprinkles (optional): For an added touch of holiday cheer, sprinkle some red, green, or festive holiday sprinkles on top of the cookies right after they come out of the oven.
3. Serve and Enjoy: Once the cookies have cooled, arrange them on a platter or serve them individually. These colorful, chewy cookies are perfect for holiday parties, cookie exchanges, or as a sweet snack with a glass of milk.