Pre-heat oven to 350F (180C). Lightly oil a medium to large baking dish.
FOR THE POLPETTONE
In a large bowl add the ground beef, Italian sausage (remove the casing and break into pieces), the parmesan cheese, moist bread, oregano, egg, salt and pepper gently combine well, form into a log and place in prepared baking pan.
FOR THE ROASTED POTATOES & ONIONS
In a large bowl toss together the cut up potatoes, onions (they can be left out if desired), rosemary, oregano, salt and olive oil. Place around the polpettone.
Bake for approximately one hour (halfway through check for excess liquid in the pan and drain carefully if necessary/or when thermometer reads 160F / 70C) . Let sit 5 minutes before cutting. Serve. Enjoy!