Heat oil in large saucepan, fry the onion until transparent.
Add the pancetta and fry until crisp.
Add the cooked beans with a little of their water (or the canned beans with their liquid),
the 2 cups of water in addition and season.
Boil (covered) for 30 minutes.
Mash the beans, and add the oats, milk and basil; cook (covered) for 15 minutes.
Add the lemon juice and stir until well combined. Serve with fresh bread if desired.