1) In a soup pot, heat the oil over medium heat, add the pancetta, and saute for about 5 minutes. Remove meat with a slotted spoon and set aside. Add the onion and saute until golden, about 10 minutes.
2) Add the garlic, rosemary, and chilli flakes; saute for 3 minutes more. Add the escarole, stirring for 2 minutes more. Add the beans, tomato, stock, and salt to taste; bring to the boil. Lower the heat to maintain a gentle simmer, cover, and cook for 10 to 15 minutes. Stir in the reserved pancetta and season with salt and pepper to taste.
Serve with a drizzle of olive oil and/or Parmesan cheese and the crusty bread.
Cook's note: Swiss chard is a welcome substitute for the escarole.