Ultimate Monster Cookies: Chewy

Ingredients

• ½ cup (113g) unsalted butter, room temperature
• 1 cup (200g) light brown sugar, packed
• ¼ cup (50g) granulated sugar
• ⅓ cup smooth peanut butter, room temperature
• 1 large egg plus 1 egg yolk, room temperature
• 2 teaspoons vanilla extract
• 2 teaspoons maple syrup
• 1 cup (115g) old-fashioned rolled oats
• 1¼ cups (155g) all-purpose flour, spooned and leveled
• 1 teaspoon baking soda
• ½ teaspoon baking powder
• ½ teaspoon kosher salt
• ¾ cup semi-sweet chocolate chips, plus more for the top
• ¾ cup M&M candies, plus more for the top