Sauté the Vegetables
In a large pot, heat the olive oil over medium heat. Add the onion, bell pepper, and jalapeño (if using) and sauté until softened, about 5 minutes. Add the garlic and cook for another minute until fragrant.
Add the Spices
Stir in the ground cumin, smoked paprika, coriander, cayenne (if using), salt, and pepper. Cook for 1-2 minutes to allow the spices to become fragrant.
Add the Beans, Tomatoes, and Broth
Add the black beans, diced tomatoes, and vegetable broth to the pot. Stir everything together until well combined.
Simmer the Soup
Bring the soup to a boil, then reduce the heat to low. Cover and simmer for 20-30 minutes, allowing the flavors to meld.
Blend for a Creamy Texture (Optional)
For a thicker, creamier soup, use an immersion blender to partially blend the soup directly in the pot, or transfer half the soup to a blender and blend until smooth. Return the blended soup to the pot and stir.
Finish with Lime Juice
Stir in the lime juice for a touch of brightness and adjust seasoning to taste.
Serve
Ladle the soup into bowls and garnish with fresh cilantro and your favorite toppings.