Preheat oven to 375F.
Combine the beef, pork, 3/4 cup Parmesan, heavy cream, egg, onion, garlic, Italian seasoning, salt and pepper in a large bowl. Mix with your hands until well combined.
Spray a casserole dish or a 9 X 13 aluminum pan with non stick spray.
Using a small cookie scoop or a tablespoon scoop out a well rounded tablespoon of the meat mixture and form into a ball. Place the meatballs side by side on the dish.
Bake meatballs for 10 to 12 minutes. Remove from oven and drain any excess fat from the pan.
Cover the meatballs with the marinara sauce. Sprinkle the remaining 1/4 cup Parmesan cheese and the mozzarella cheese evenly over the meatballs.
Place back in the oven and cook another 15 to 20 minutes or until the meatballs are cooked through and the internal temperature is 160F.
Remove and garnish with parsley if desired. Serve with your favorite side dishes.