1-Start: Start by beating 1 cup of unsalted butter until it’s smooth and creamy. Then, add 1 cup of creamy peanut butter and 2 teaspoons of pure vanilla extract, beating until well combined. This step ensures your base is perfectly blended for that rich flavor.

2-Next: Next, mix in 1 and 1/4 cups of packed light brown sugar and 1/3 cup of granulated sugar. Beat until the mixture is light and fluffy, scraping the bowl as needed to get everything even.

3-Add: Add 2 large eggs and 1 large egg yolk one at a time, beating well after each addition. Using room-temperature eggs helps them blend smoothly and gives your cookies that soft texture.

4-In a separate bowl, whisk together 1 and 3/4 cups of all-purpose flour, 3/4 cup old-fashioned oats, 1/2 cup quick oats, 1 teaspoon baking soda, 1 teaspoon baking powder, 1/2 teaspoon ground cinnamon, and 1/2 teaspoon salt.

5-Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. Be careful not to over-mix, as that can make your cookies tough.

6-Gently fold in 1 and 1/2 cups of M&M candies, 1 and 1/2 cups of semi-sweet chocolate chips, and 1/2 cup of roughly chopped salted peanuts using a spatula. This adds the fun mix-ins that make these cookies monster-licious!

7-Cover the dough and chill it in the refrigerator for at least 30 minutes, or up to 2 days. Chilling helps enhance the flavor and prevents spreading.

8-Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper for easy cleanup.

9-Scoop the chilled dough into 2-tablespoon mounds onto the prepared sheets, leaving space between them. Slightly flatten each mound and optionally sprinkle extra oats on top for a nice finish.

10-Bake for about 12 minutes, or until the edges are golden and the centers are set. Keep an eye on them to get that perfect chewy edge and soft center.

11-Finally, cool the cookies on the baking sheet for 10 minutes before moving them to a wire rack to cool completely. This lets them set up just right.