Back in college, a great local cafe stayed opened into the wee hours ladling up their version of this stuff. The first time I slurped some of it down after midnight, I decided to make black bean soup my own tradition. Mine is hearty and smoky, and if it's lying around, I'll also throw in a can of beer for good taste and in keeping with the spirit of a good night on the town. Like the onion soup, you'll want to make this ahead of time so you're not faced with the prep-work when you and your friends just want to kick back and chow down after a long night. Using smoked bacon makes all the difference in the world because those beans are just begging for that rich, smoky flavor.
Meanwhile, pick off all the thick stems from the cilantro. Wash it and shake dry. Chop the cilantro coarsely and stir it into the soup when it has been simmering 10 minutes. cook until the soup is thickened, about 5 minutes. Stir in the lime juice. Serve with the garnishes.