Instructions

1. In a large mixing bowl, combine the brownie mix, oil, and egg (or egg + egg yolk). Note that the batter will be very thick. Fold in the chocolate chips or chunks now, if desired. Set the batter aside for about 15 minutes to allow the dry ingredients to hydrate while they oven preheats.
2. Heat oven to 350 degrees. Line a baking sheet or two with parchment paper or a silicone baking mat. 
3. Use a medium cookie scoop to portion out the batter into 2-tablespoon balls onto the prepared baking sheets. The cookies will spread while baking, so I recommend only placing 8 cookies per baking sheet.
4. Bake at 350 degrees for 9-10 minutes. My brownie cookies were perfectly cooked at 10 minutes in a 350 degree oven, but I would recommend starting to check them around the 9-minute mark. Add an extra minute as needed; however, take care not to over bake them. They’re done when they’re no longer shiny on top, even though they may still look slightly underbaked overall.
5. Cool on the baking sheet for 5 minutes before transferring to a wire cooling rack.