Grate the bread or pulse into crumbs in a food processor. In a small bowl toss the bread crumbs with 1/3 cup cold water to re-hydrate.

In a large bowl, combine the bread crumbs, Italian sausage, beef, Parmesan, Romano, parsley, salt, onion, garlic, and egg and mix until combined. Season the meat mixture with pepper.

Using your hands, gently form the meat mixture into slightly larger than golf ball-sized balls. Refridgerate for 1 to 24 hours.

Heat half the oil in a large non-stick skillet over medium high heat. Add half of the meatballs and cook, turning occasionally, until well browned, about 6 minutes. Repeat for the remaining meatballs.

Drain meatballs, then add to a marinara sauce or tomato sauce. Bring to a boil, then lower heat and simmer, stirring occasionally, about 15 minutes.