2 tablespoons vegetable oil
1 large onion, diced
1 large sweet potato, peeled and diced
4 garlic cloves, minced
1 tablespoon minced chipotle chile in adobo sauce
2 tablespoons chili powder
2teaspoons ground cumin
½ teaspoon kosher salt
2½ cups water
2 (15-ounce) cans black beans, rinsed
1 (14-ounce) can diced tomatoes
1 tablespoon freshly squeezed lime juice
½ cup chopped cilantro
Heat the oil in a stockpot or large saucepan over medium-high heat.
Add the onion and sweet potatoes and cook, stirring frequently, until the onion is soft and translucent, about 5 minutes.
Add the garlic, chili powder, cumin, chipotle chile, and salt. Cook, stirring constantly, for 1 minute.
Stir in the water and bring to a simmer. Reduce the heat to low, cover, and simmer for about 15 minutes, until the sweet potato is tender.
Stir in the black beans and tomatoes. Continue to simmer, stirring frequently, for about 5 minutes, until the sauce thickens a bit.
Just before serving, stir in the lime juice and cilantro.