Heat pancetta (or bacon) in a large stockpot over medium-high heat.  Cook until crispy, stirring occasionally.  Transfer the bacon to a separate plate, using a slotted spoon, reserving about 3 tablespoons of bacon grease in the stockpot.  (Discard any extra grease, or you can substitute olive oil in place of the 3 tablespoons of bacon grease.)

Add onion and cook for 5 minutes, stirring occasionally, until soft and translucent.  Add garlic and cook for 1-2 minutes until fragrant, stirring occasionally.

Add chicken stock, beans, bay leaf, rosemary and half of the cooked pancetta (or bacon).  Stir to combine.  Continue cooking the soup until it reaches a simmer.  Then reduce heat to medium-low, cover partially, and let the soup simmer for 10-20 minutes so that the flavors will meld.

Add salt and pepper to taste.  (I definitely recommend a generous pinch or two of black pepper, and extra salt if needed, depending on your chicken stock.)  Remove the bay leaf and rosemary.

Serve warm, topped with the extra pancetta (or bacon).  Garnish with Parmesan and serve with Italian bread if desired.