1 medium poblano chile
2 tsp. canola oil
1 medium onion, finely chopped
2 cups cooked black beans, plus 3 tbsp. of the cooking liquid
salt and freshly ground pepper
1 tbsp. chopped fresh cilantro

Roast poblano directly over a gas flame or under the broiler as close to the heat as possible, turning frequently, until charred all over.
Transfer to a paper bag; close the top, and let steam for 10 minutes.
Scrape off the skin and discard the core, seeds and ribs, and finely chop. Heat the oil in a medium nonstick skillet. Add the onion and cook over moderately high heat, stirring occasionally, until golden, about 5 minutes.
Reduce the heat to low and stir in the beans and their liquid. Using a wooden spoon, stir and mash the beans to a rough puree. Add the poblano and stir until the beans are heated through, about 3 minutes. Season with salt and pepper.
Transfer the beans to a serving dish and sprinkle with cilantro.

Serves 4.