Preheat the oven to 350°F. Line two baking sheets with parchment paper.
Whisk the eggs and oil in a large bowl until smooth and glossy.
Stir in the brownie mix until a thick, sticky dough forms with no dry spots.
Scoop heaping tablespoon mounds onto the sheets, spacing about 2 inches apart.
Bake 9–11 minutes, until the tops crack and the edges look set but centers are soft.
Cool on the pan 5 minutes, then transfer cookies to a rack to finish cooling.