Preheat oven to 350° F (180°C).
Mix together the brownie mix, melted butter, egg and flour.
The dough should be quite soft, if your dough is pretty stiff, mix in 1 tbsp of milk or else your cookies will not spread at all. If your dough is soft, you can omit the milk.
Mix in your chocolate chips.Scoop into equal sized balls and arrange on a cookie sheet.
For small cookies, use 1 1/2 tbsp of dough (#50 scoops). For medium sized cookies, use 3 tbsp of dough.
Bake at 350°F (180°C) for 8-11 minutes or until the tops are no longer glossy.
Let cool for 5-10 minutes before transferring to a wire cooling rack.