3 Bean Vegetarian Chili

1 tablespoon olive oil
1 onion, diced (1 cup)
1 red bell pepper, diced (1 cup)
2 carrots, diced (1/2 cup)
2 teaspoons ground cumin
1 (28-ounce) can crushed tomatoes
2 cups water (or broth)
1 chipotle chile in adobo sauce, seeded and minced
2 teaspoons adobo sauce from the can of chipotles (or a 4oz can of diced chilis)
1/2 teaspoon dried oregano
Salt and freshly ground black pepper
1 (15.5-ounce) can black beans, drained and rinsed
1 (15.5-ounce) can kidney beans, drained and rinsed
1 (15.5-ounce) can pinto beans, drained and rinsed

Heat the oil in large pot or Dutch oven over moderate heat. Add the onion, bell pepper and carrots, cover and cook, stirring occasionally until the vegetables are soft, about 10 minutes. Add the cumin and cook, stirring, for 1 minute. Stir in the tomatoes, water, chipotle and adobo sauce, oregano and salt and pepper. Cook, partially covered, stirring from time to time, for 30 minutes. Stir in the beans and continue cooking, partially covered, 20 minutes longer. Season, to taste, with salt and pepper.