Preparation

1. 1. Insert the chopping blade into the work bowl of the food processor. Add the carrot and zucchini to the work bowl and pulse to roughly chop. Remove and reserve. With the machine running on Low, drop the garlic through the feed tube to finely chop. Scrape down the sides of the bowl. Add the onion and pulse to finely chop.
2. 2. Put the oil in a medium sauté pan set over medium heat. Once hot, add the garlic, onion, ¼ teaspoon of salt, and the pepper.. Sauté until softened and fragrant, about 5 minutes. Add the black beans, chipotle and sauce, and enough water to keep the pan from being dry. Cook until beans are soft enough to be easily mashed, about 10 minutes, adding additional water as needed to prevent the pan from going dry.
3. 3. Once beans are soft, add the remaining salt, quinoa, carrot, and zucchini. Add additional water, about 2 to 3 tablespoons, stir, partially cover and reduce heat to medium-low and cook vegetables until just softened, about 5 minutes. Let cool slightly.
4. 4. Transfer the mixture to the work bowl of the food processor. Add the cilantro and pulse until mixture is blended but not puréed.
5. 5. Form mixture into ¹⁄³-cup patties. Heat remaining oil in a large cast-iron skillet over medium heat. Working in batches, cook patties until dark brown on both sides, about 10 minutes total. Place cheese, if using, over burgers for the last minute to melt.
6. 6. Serve burgers on toasted buns smeared with mayo, if desired, and choice of toppings.