Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a medium bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking powder, 1 teaspoon of baking soda, and ½ teaspoon of salt.

In a large mixing bowl, cream together ½ cup of softened butter, ½ cup of granulated sugar, and ½ cup of packed brown sugar for 3-5 minutes until smooth.

Beat in 1 lightly beaten egg and 1 teaspoon of vanilla extract into the butter mixture until fully combined.

Gradually mix in the dry ingredients until a dough forms, about 1-2 minutes.

Scoop about 2-3 tablespoons of dough, roll into balls, and place on the prepared baking sheet 2-3 inches apart.

Bake for 10-12 minutes, until edges are slightly browned and centers appear soft.

Gently press 9 pastel M&Ms into the top of each cookie while warm.

Allow to cool on the baking sheet for about 5 minutes, then transfer to a wire rack to cool completely.