Tear the crustless bread into small pieces and place in a medium bowl. Pour the milk over the bread and press with your fingers, to help the milk get absorbed. Let it rest for about 5 minutes.
4 slices Italian bread, 1 cup whole milk
In a large mixing bowl, mix together the beef, pork, veal, and eggs. Mix until just combined.
1 lb beef, 1 lb pork, ½ lb veal, 2 large eggs
Now add the breadcrumbs, parsley, basil, salt, garlic, and pepper and mix it well.
½ cup breadcrumbs, 3 tbsp parsley, 2 tbsp basil, 3 cloves garlic, 1 tbsp Kosher salt, 1 tbsp freshly ground black pepper
Add the soaked bread and Parmesan cheese to the meat mixture and mix until fully combined.
1 cup Parmesan cheese
Pull out chunks of meat and roll them between your hands that have been dampened with water. Each ball should be slightly larger than a golf ball, approx. 3 oz. each. Place the balls on a baking sheet lined with parchment paper. Refrigerate the rolled balls for 15 minutes to 1 hour.
Meanwhile, preheat oven to 375°F.
Bake meatballs for 30 minutes. Flipping once, halfway through cooking.
(Alternatively, you can brown the meatballs in a skillet with olive oil - about 1 tablespoon - until browned on all sides).
Meanwhile, in a large skillet or pot, heat the marina over medium heat.
4 cups fresh marinara sauce
Carefully add the meatballs and any accumulated juice to the marinara.
Lower the heat to medium and cook them for at least 20 to 30 minutes, or up to 1 hour. Add more marinara, if necessary. You'll need to turn the balls over now and then if they are not fully submerged.
Use tongs to remove the meatballs from the sauce and place them in a serving bowl. Ladle on a little sauce and grate fresh Parmesan cheese over the top. Garnish with chopped parsley (if using).
Serve at once with extra sauce on the side. Or, place them in a slow cooker on the WARM setting.