Wash the beans and soak them in the evening in cold water to make them easier to boil the next day. The next morning, pour in water and put the beans to boil.
To the boiled beans, add the chopped celery (root) and carrots. Boil until soft. Top up using boiling water. When the beans become tender, make a roux from the finely chopped onion, by putting it in boiling oil. Stew the onions until they turn glassy in appearance. Add the flour and after it turns golden, add in the tomato puree or tomatoes.
Stir the resulting mixture with broth from the beans until diluted. Pour it into the main soup. Add salt if there's no butterfat in the soup. Pour in 1/4 cup of cold water in a pot of 6 servings.
Serve sprinkled with finely chopped spearmint or parsley. You can make the soup without paprika and instead with more vegetables and a root of savory.