To double-peel fava beans:

Shell the beans. Bring a large pot of water to a boil over high heat. Add beans and boil 2 minutes if large, 1 minute if small; drain and transfer to a bowl of ice water. Drain when cool, then remove the outer skin from each bean by pinching open the end of the bean opposite the end that connected it to the pod. The peeled bean will slip out easily. You should have about 1 to 1¼ cups peeled beans.

Saute pancetta in olive oil in a skillet over moderately low heat until it renders most of its fat and begins to crisp, about 5 minutes. Add shallots and sauté until softened, about 1 minute.

Put frisée in a serving bowl. Add contents of skillet, parsley and vinegar.

Toss well, then add favas, season with salt and pepper and toss again.

Taste and adjust seasoning.