Prep a 9x9" square baking dish (for thick brownies) or a 9x13" dish by greasing it or lining with parchment paper.
Stir together brownie mix, avocado, and water until combined. Bake as directed on the brownie mix package erring on the side of baking a minute or two more than normal.
To cut picture perfect brownies, slice into cooled brownies with a plastic knife.
Recipe by Jellibean Journals at https://jellibeanjournals.com/skinny-avocado-brownies/