Heat olive oil in a large pot over medium heat.
Add diced onion and green bell pepper.
Cook 5–6 minutes until vegetables soften.
Add minced garlic and cook 1 minute until fragrant.
Stir in cumin, oregano, paprika, black pepper, salt, and bay leaf.
Cook 30–60 seconds to bloom the spices.
Add black beans with their liquid.
Pour in broth, vinegar, and sugar.
Stir and bring mixture to a boil.
Reduce heat and simmer uncovered 25–30 minutes.
Mash about ⅓ of the beans with a fork or potato masher.
Adjust consistency with broth or water if needed.
Taste and adjust seasoning.
Remove bay leaf before serving.
Garnish with cilantro if desired and serve hot.