My Best M&M Cookie Recipe

Ingredients

• ½ teaspoon baking powder
• ¼ cup granulated sugar
• ¾ cup tightly packed light OR dark brown sugar
• 2 teaspoons pure vanilla extract
• flaky salt, for garnish
• 1 ⅔ cup all-purpose flour
• ½ teaspoon baking soda
• 1 teaspoon kosher salt
• 1 large egg
• ½ cup different M&M varieties , plus more for garnish
• ½ cup unsalted butter, melted and cooled slightly
• 4 ounces dark chocolate , from whole fèves or a high-quality chocolate bar roughly chopped into 1- to 1 ½-inch pieces