Crumble bread into a bowl and mix in milk thoroughly using a fork. Let stand for 10 to 15 minutes.
Combine beef and pork in a large bowl and mix well using 2 forks. Add salt, black pepper, oregano, onion powder, garlic powder, cayenne, olive oil, Parmesan, parsley, eggs, and the breadcrumb mixture. Mix using 2 forks until everything is evenly combined. Wrap and chill in the refrigerator for 1 hour.
Preheat the oven to 400 degrees F (200 degrees C). Lightly grease a roasting pan or baking dish. Using damp hands, roll 4 giant meatballs, and place in the prepared pan.
Bake in the preheated oven until an instant read thermometer inserted near the center of meatballs reads 160 to 165 degrees F (71 to 74 degrees C), 40 to 45 minutes.
Remove meatballs from the oven, and spoon tomato sauce evenly over meatballs. Sprinkle first with Monterey Jack cheese, and then with Parmigiano-Reggiano.
Return meatballs to the oven, and bake until sauce is hot and cheese is melted, 5 to 10 minutes more. Top with parsley and serve.
