In a small bowl, soak bread in milk. Tear with hands until it resembles a soft paste.
In a large bowl, combine ground beef, ground pork, soaked bread, onions, eggs, salt and Italian seasoning. Gently mix until combined.
Using a small scoop, portion about 1 tablespoon of meat mixture and using roll between palms of hands into a 1-inch diameter ball.
Arrange meatballs in a single layer on a parchment-lined baking sheet and freeze for about 20 to 30 minutes or until firm.
In a skillet over medium heat, heat oil. Add meatballs in a single layer and cook, gently turning on sides as needed, until lightly browned but not cooked through. Remove from pan and drain on paper towels. Keep warm.
Alternatively, arrange meatballs in a single layer on a baking sheet and bake in a 400 F oven for about 10 to 15 minutes or until no longer pink.
In another pan over medium heat, heat the remaining 1 tablespoon oil.
Add tomato sauce, heavy cream, and water. Season with salt and pepper to taste. Stir to combine and bring to a simmer.
Add meatballs in a single layer and cook, stirring occasionally, for about 8 to 10 minutes or until meatballs are until thermometer inserted in the center of meatball reads 145 F.
Sprinkle with Parmesan cheese, if desired. Serve hot.