Finely dice your onion, carrots, and celery.
Mince your proscuitto, mortadella, and ground pork.
Add the olive oil to a large saute pan over medium-high heat and deeply caramelize the onions, carrots, and celery, about 5 minutes.
Add the meats, parmigiano rind, and enough stock to cover, then reduce the heat to a bare simmer. Cover and simmer for 6-7 hours, checking on it every hour or so to make sure it hasn't gone dry. Add stock as necessary.
After simmering, add the cheese, then season with salt, if necessary.