Soak beans overnight, or boil for 3 minutes and then soak for 1 hour. Drain beans, discarding the soaking liquid. Simmer beans in stock with onion, garlic, and bay leaves until beans are tender, about 1 hour. Blanch pancetta in boiling water for 5 minutes. Drain, and add to the soup halfway through cooking.
Wash escarole, and pat dry. Roughly chop escarole; set aside.
When beans are thoroughly cooked, add chopped escarole. Simmer for 2 minutes, and season to taste with salt and pepper.