Preheat your oven to 325°F (163°C).

In a large mixing bowl, whisk together the melted unsalted butter, light brown sugar, and granulated sugar until well combined and smooth.

Add 1 large egg and 2 teaspoons of pure vanilla extract to the mixture and mix until fully incorporated.

In a separate bowl, whisk together 2.5 cups of all-purpose flour, 1 teaspoon of baking soda, 1 teaspoon of baking powder, and 0.5 teaspoon of salt.

Gradually add the dry mixture into the wet ingredients, stirring gently until just combined.

Fold in 1 cup of mini M&M's and 1 cup of mini semi-sweet chocolate chips until evenly distributed.

Scoop dollops of dough onto a lined baking sheet, spaced 2-3 inches apart.

Bake for 10-12 minutes, until edges are golden brown but centers look slightly underbaked.

Cool on the baking sheet for about 5 minutes before transferring to a wire rack to cool completely.