Step 1: Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper to prevent sticking and ensure easy cleanup.
Step 2: In a large mixing bowl, combine the entire contents of the brownie mix box, 2 large eggs, 1/4 cup vegetable oil, and 2 tablespoons of all-purpose flour.
Step 3: Stir the ingredients together using a spoon or spatula until a thick, dense dough forms. Avoid overmixing; stir just until combined.
Step 4: If desired, gently fold in 1/2 cup of chocolate chips or any other preferred mix-ins.
Step 5: Scoop tablespoon-sized portions of the dough and roll them into smooth balls. Place them approximately 2 inches apart on your prepared baking sheet.
Step 6: Bake for 8 to 10 minutes. The cookies are done when the edges are set and the centers still look slightly soft. They will firm up as they cool.
Step 7: Let the cookies cool on the baking sheet for 2–3 minutes before carefully transferring them to a wire rack to cool completely. This helps them retain their shape and chewy texture.