Rolling Mix: In a small bowl, combine the 1/4 cup granulated sugar and 2 teaspoons cocoa powder and set aside.
Dry Ingredients: In a large bowl, whisk together the brownie mix and additional 2 tablespoons flour.
Wet Ingredients: In a medium bowl, whisk together the melted (and slightly cooled!) butter, vanilla, and eggs until smooth.
Combine: Add the butter mixture to the dry ingredients and stir with a spatula or wooden spoon until almost combined, then add the chocolate chips and mix until no flour is visible (be careful not to over mix). It will be thick. Let dough chill (covered or uncovered) for about 15 minutes in the refrigerator.
Prep: While the dough is chilling, preheat oven to 350°F. Line a cookie sheet with parchment paper or silpat or grease with cooking spray.
Roll: Form balls using about 1 1/2 tablespoons of dough and roll in the sugar and cocoa mixture before placing on the cookie sheet about 1-2 inches apart. (No need to press them down.)
Bake: Bake about 12 minutes (rotating halfway) until the edges are set. Let cool for about 10 minutes before transferring to a wire rack to finish cooling. They may seem doughy in the middle when you remove them from the oven, but the cookies will set as they cool.