Cut the pancetta into wide ribbons
Cook the onion in the oil until it becomes translucent, then add the pancetta strips and cook for 2 to 3 more minutes
Stir in beans. Season with a little pepper
Add stock or water and simmer, covered, on low heat for 8 to 10 minutes. Add more water if necessary.
When the beans are tender, add salt, pepper to taste, ,and cook for a few more minutes uncovered until the last of the liquid has evaporated
Serve with thin slices of pecorino over the beans