If using dried beans, soak them overnight. Drain and rinse.

Heat olive oil in a large pot over medium heat. Add chopped onion and cook until softened, about 5 minutes.

Add minced garlic, cumin, oregano, and chili powder (if using) and cook for another minute until fragrant.

Add the soaked and drained black beans and vegetable stock to the pot. Bring to a boil, then reduce heat and simmer for 45-60 minutes, or until the beans are tender.

Carefully blend the soup using an immersion blender or transfer to a regular blender (in batches) until smooth or desired consistency is reached.

Stir in lime juice, salt, and pepper to taste.

Serve hot, garnished with your favorite toppings (e.g., a dollop of sour cream, chopped cilantro, or a squeeze of lime).