In a large mixing bowl, combine 1 box (18 oz) brownie mix, 1 cup flour, 3 eggs, and ? cup vegetable oil.
Stir the mixture with a wooden spoon or sturdy plastic spoon until fully combined. The dough will be very thick.
Place ½ cup powdered sugar in a small bowl.
Scoop the cookie dough using a cookie scoop and roll each dough ball in the powdered sugar until coated.
Place the cookies 2 inches apart on an ungreased baking sheet.
Bake for 8–10 minutes, until the cookies are set.
Remove from the oven and allow the cookies to cool on the baking sheet for 5 minutes.
Transfer the cookies to a wire rack to cool completely.
Serve and enjoy!
Notes
*Store these cookies in an airtight container at room temperature for up to 1-2 weeks. Keep a piece of bread in the container with the cookies to keep them moist while you store them.