Recipe Instructions:
2 (15-ounce) cans black beans, drained and rinsed (about 3 1/3 cups)
3/4 cup old-fashioned rolled oats
1 canned chipotle in adobo chile, plus 1 tablespoon adobo sauce
3/4 teaspoon kosher salt
1/4 teaspoon freshly ground black pepper
2 large avocados, divided
1/4 cup coarsely chopped fresh cilantro leaves and tender stems
2 to 3 tablespoons olive or canola oil
For serving: Hamburger buns, chipotle mayo (see above for a homemade version), sliced red onion, tomato slices, and Bibb lettuce leaves
Arrange a rack in the middle of the oven and heat to 350°F. Spread the beans onto a rimmed baking sheet. Bake until dry to the touch and beginning to split, 10 to 12 minutes. Set aside to cool, about 5 minutes.
Place the cooled beans, oats, adobo and sauce, salt, and pepper in the bowl of a food processor fitted with the blade attachment. Process until the beans and oats are broken down and mixture begins to come together, scraping the sides as needed, 15 to 20 seconds; set aside.
Place half of 1 avocado in a large bowl and mash with a fork until smooth (you should have about 1/2 cup mashed avocado). Reserve remaining half for topping the burgers. Add the bean mixture to the bowl and stir and fold with a rubber spatula until a cohesive mixture forms. Add the cilantro and stir to incorporate.
Shape the mixture into 4 (2/3 cup) patties or 6 smaller (1/2 cup) patties. Let rest for 5 minutes, or refrigerate for up to 3 hours.
Heat 2 tablespoons of the oil in a large skillet over medium-high heat until shimmering. Add the patties and cook until a dark crust forms on the bottom of the patties, 3 to 4 minutes. Flip and cook until crisp on the other side, 3 to 4 minutes more (if making 6 burgers, work in batches, adding 1 tablespoon oil to pan for second batch). Coarsely mash the remaining avocado half and as much of the second avocado as you desire. Spread mashed avocado onto buns. Serve burgers on buns with chipotle mayo, onion, tomato, and lettuce.
