Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a medium mixing bowl, whisk together the eggs and vegetable oil until smooth.
Pour in the boxed brownie mix and stir until combined. The dough will be thick and sticky.
Add the all-purpose flour and mix until no dry streaks remain.
Fold in chocolate chips or other mix-ins if desired.
Use a tablespoon or cookie scoop to drop dough balls onto the prepared baking sheet, leaving space for spreading.
Bake for 8–10 minutes, until edges are set but centers remain soft.
Cool on pan for 2–3 minutes, then transfer to a wire rack.
