Directions

1. Cook beef and chorizo in a 12-inch frying pan over medium-high heat, breaking them up, until barely cooked through, about 5 minutes. Add onion and cook, stirring occasionally, until slightly softened, about 3 minutes. Add bell pepper, carrots, and garlic and cook, stirring occasionally, until vegetables are crisp-tender, about 5 minutes.
2. Stir in tomatoes (with their juices), chicken broth, beans, chipotle powder, tomato paste, cumin, and 1 tsp. salt, scraping up any browned bits in the pan. Bring to a boil and reduce heat to a simmer. Cover and cook, stirring occasionally, until vegetables are tender, about 15 minutes.
3. Meanwhile, preheat the broiler with a rack 4-6 inches from heat. Arrange hamburger buns, cut side up, on a sheet pan. Toast until lightly browned, 2-3 minutes.
4. In a small bowl, combine water and cornstarch. Add cornstarch mixture to beef mixture and cook, stirring, until sauce thickens, 30-60 seconds. Add lime juice. Season to taste with hot sauce and with more salt if you like.
5. Open up each bun on a plate. Top with sloppy Joe mixture and then with sour cream and cilantro.