This soup had its origins in a recipe for black beans and rice (Cristianos y Moros) that I clipped from the New York Times in the early 70’s.
It was one of the many classic rice and bean dishes we made in those long ago days of serious complimentary proteins. I cannot recall when or where it lost the rice. Needless to say, the soup can easily revert to its rice and bean origins.
Over the years, due to vegetarian Sam, I've cut out the ham--and although I’m always one to argue for the superiority of a little ham/bacon/smoky flavor, we have adapted very well to the vegetarian version.
Soak 1 pound of black beans over night or for an appropriate number of hours.
Cover the beans with water—more if you’re going for the soup variation--add an onion, some garlic, celery with leaves, carrots,--your basic soup vegetables--bring to a boil, then set to simmer.
While the beans are cooking, make a sofrito:
Finely chop two to three onions, five or six cloves garlic, two red or green peppers, and perhaps a chipotle pepper as well.
I often use a food process to chop the vegetables into something that's almost a puree. It then completely dissolves in the soup.
Heat oil in a heavy pot. Add the vegetable mixture as well as a bay leaf and a bit of thyme (I often forget the thyme--that's o.k. too). When the vegetables are good and soft--not browned---add a small can of tomato paste. The original recipe calls for two or three tablespoons, but I'm always tempted --mostly because I assume I’ll forget to use the remainder--to use the entire can.
By now the beans should be cooking nicely. Add the sofrito, and keep cooking until beans are tender.
Back in the day, before immersion blenders, I would blend some of the soup in the blender, but now I’d recommend a few spins with an immersion blender.
At the end, I used to add a little vinegar, and then serve with slices of lemon. This year, my sister passed on a moosewood version--with some oranges or orange juice--I believe this particular Moosewood soup is called Brazilian black bean soup.
Eventually, by whatever path you pursue, you should have a lovely mahogany hued soup. Serve with sour cream, chopped scallions, and chopped cilantro.