Preheat oven to 350º F.

In a separate small bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.

In a mixing bowl beat the butter and brown sugar with an electric mixer for 1 minute, or until combined.

Add in the egg and vanilla extract, beating until well incorporated.

Gradually add the dry ingredients to wet ingredients, stopping to scrape down the sides of the bowl.

Use a cookie scoop to drop dough balls onto a silicone lined baking sheet. Press mini chocolate chips and M&M's around the outside of the dough balls.

Bake for 9-11 minutes. Allow the cookies to cool slightly on the baking sheet then move them to a cooling rack to cool completely. Store covered.