2 tablespoons extra-virgin olive oil2 ounces prosciutto, chopped 1 medium onion, chopped 3 cloves garlic, sliced thin 1 pound fresh collard greens, rinsed and chopped 1 tablespoon red wine vinegar Salt and freshly ground black pepper 1 pound penne 3 ounces freshly grated pecorino romano.
Heat the oil in a large, heavy skillet. Add the prosciutto and onion and cook over medium heat until they barely begin to brown. Stir in the garlic, cook a couple of minutes longer, then add the collards.
Cook, stirring, about seven minutes, until the collards have wilted. Stir in the vinegar and season to taste with salt and pepper. Remove the skillet from the heat.
Bring a large pot of salted water to boil. Add the penne, stir once or twice and cook until al dente, for about eight minutes. Remove half a cup of water from the pot; set aside. Drain the penne well.
Reheat collard mixture, add penne to the skillet and stir. Moisten with reserved cooking water and season to taste with salt and pepper. Toss with the cheese and serve.