Position a rack in the center of the oven and preheat the oven to 350°F (180oC). Line two baking sheets with parchment paper.
In a large bowl, using an electric mixer, beat together the butter, peanut butter, and both sugars on medium-high speed. Add the eggs, baking soda, and vanilla and beat well to combine. Fold in the oats, chocolate chips and m and m candies stir until incorporated. ¼ cup (4 Tablespoons, 57 g) unsalted butter 1 cup (270 g) smooth peanut butter ¾ cup (160 g) packed light brown sugar ½ cup (100 g) granulated white sugar
Add the eggs, baking soda, and vanilla and beat well to combine. 2 large eggs lightly beaten 1 ½ teaspoons baking soda 2 teaspoons pure vanilla extract
Fold in the oats, chocolate chips and m and m candies stir until incorporated. 3 cups (267 g) old fashioned rolled oats 1 cups (340 g) semi-sweet chocolate chips 1 cup M&M chocolate candies
Using a small scoop or a teaspoon, scoop out balls of dough and drop them onto a prepared baking sheet about 2 inches apart.
Bake until the cookies are lightly browned, about 12 to 14 minutes. Remove from the oven and allow to cool for about 5 minutes on a baking sheet. Transfer to a wire rack to cool completely.
Store in an airtight container at room temperature for up to 1 week.