How to Make It
In a large skillet, heat the oil. Add the pancetta and cook over moderate heat until crisp, about 8 minutes. Transfer the pancetta to a plate.
Add the onion to the skillet and cook over moderate heat, stirring occasionally, until softened. Add the cabbage and pancetta and cook, stirring, until the cabbage is tender, about 4 minutes. Remove from the heat. Stir in the vinegar, season with salt and pepper and serve.