Place the onion into the food processor. Blitz until the onion is throughly chopped.
In a food processor, place the bologna, pork, bread crumbs, parmesan, egg, pepper, salt, vinegar and rosemary. Blitz until thoroughly combined.
Using a 2-inch ice cream scoop, scoop individual meatballs and place into the stock pot of simmering red sauce. Cover and cook until meatballs reached 165 degrees, about 30 minutes to 1 hour.
Serve the meatballs with your favorite pasta, topped with the red sauce, grated parmesan and chopped fresh basil leaves.