- 2 eggs
- 1/3 cup water
- 1/3 cup vegetable oil
- 1 (19.8 ounce) package brownie mix
- 1 ripe banana, mashed
- 1/2 cup chopped walnuts, or to taste
- 1/4 cup confectioners' sugar (optional)
- Preheat oven to 350 degrees F (175 degrees C).
- Beat eggs, water, and vegetable oil together in a large bowl until smooth; add brownie mix and stir until the mixture is a smooth batter. Beat mashed banana into batter; fold in walnuts. Pour batter into a 13×9-inch baking dish.
- Bake in preheated oven until set in the middle, about 23 minutes.
- Cool brownies at room temperature for 10 to 15 minutes before cutting into bars. Sprinkle confectioners' sugar over the brownies.