- 2 (15 ounce) cans no-salt-added black beans, drained
- 2 1/2 cups ripe bananas
- 4 teaspoons vanilla extract
- 3 1/2 cups pitted chopped dates, or more to taste
- 1 1/3 cups oat flour
- 1 cup cocoa powder
- 2 tablespoons ground flax seed
- 4 teaspoons baking powder
- 2 teaspoons baking soda
- 2 cups chopped walnuts
- Preheat oven to 350 degrees F (175 degrees C). Grease a 9×13-inch baking dish.
- Blend black beans in a blender until smooth. Add bananas and vanilla extract; blend until smooth. Gradually add dates, a few at a time, and blend until evenly incorporated.
- Whisk oat flour, cocoa powder, flax seed, baking powder, and baking soda together in a bowl. Beat bean mixture into flour mixture on low to medium speed until batter is well blended; fold in walnuts. Spoon batter into prepared baking dish.
- Bake in the preheated oven until edges of brownies begin to pull away from sides of dish, about 50 minutes.