In a casserole put a splash of oil, add the onion and garlic chopped very small. Gently fry. Add the diced bacon, minced small pork rib and mint leaves.
Once brown, add the beans and sofrito for a while. Then pour water to cover. When boiling, add the bouillon cube. Stir, season, cover and reduce heat. Simmer slowly.
When you see they are almost cooked, add the black sausage into pieces 2 centimeters. Try the salt and if they are to your liking, turn off the heat. If left to stand a little will catch better taste.