From My Bowl

0 Sauté: Warm the oil in a large pot or dutch oven over medium-high heat. Add the onion and bell peppers and sauté for 7 to 9 minutes, stirring occasionally, until the onion is beginning to brown. Reduce the heat to medium.
1 Aromatics: Add the garlic, finely diced cilantro stems, cumin, oregano, and cayenne pepper, if using. Mix well and sauté for 2 to 3 minutes, until the spices begin to stick to the bottom of the pot.
2 Simmer: Add the black beans, tomatoes, and vegetable broth. Mix well and bring to a boil over high heat, then reduce the heat to medium and simmer for 20 minutes, stirring occasionally. If the soup begins to splatter, reduce the heat to medium-low, but maintain a simmer.
3 Thicken the Stew: Add the masa harina to a small bowl. Whisk 1/2 cup of warm water into the masa harina, add  . Add the paste to the simmering soup and stir well. Simmer the soup for an additional 5 to 10 minutes, until it has thickened to your liking; stir frequently to prevent anything from sticking to the bottom of the pot. If the soup gets too thick, thin it out with water in 1/2 cup increments.
4 Final Touches: Turn the heat off and stir in the lime juice and 2 tablespoons of the chopped cilantro leaves. Add salt or additional seasonings to taste, as necessary.
5 Serve: Serve warm, topped with the remaining cilantro leaves. Store any leftovers in the refrigerator for up to to 5 days. You can also store this stew in the freezer for up to 2 months.