Step 1

Make the meatballs: Preheat oven to 350 degrees.

Step 2

Run bread under water and gently squeeze out excess liquid. Transfer bread to a large bowl and add veal, beef, pork, egg, onion, parsley, basil, cheese, and oregano; season with salt. Using your hands, mix until well combined. Divide mixture into 8 equal portions and roll each portion into a large round meatball. Place meatballs in a large baking dish.

Step 3

In a large bowl, combine tomato sauce and two cups of water. Spoon tomato sauce mixture over meatballs until liquid comes three-quarters of the way up the meatballs, adding more water if necessary. Cover baking dish with parchment paper-lined aluminum foil and transfer to oven. Bake meatballs for 1 hour, rotating dish after 30 minutes.

Step 4

Make the stuffing: In a medium bowl, mix together all ingredients. Transfer cheese mixture to a pastry bag fitted with a large plain round tip; set aside.

Step 5

Remove meatballs from baking dish and discard liquid. Using an apple corer or small knife, cut out a 1/2-inch hole in the bottom of each meatball; fill hole with cheese mixture and transfer meatballs to a large baking dish, hole side up.

Step 6

Serve: Preheat oven to 350 degrees. Spoon tomato sauce evenly over meatballs and transfer to oven. Bake until heated through, 10 to 15 minutes. Top each meatball with a tablespoon of ricotta cheese (it should look like it is oozing from the center) and sprinkle with Parmigiano; return to oven and heat for 3 minutes. Serve immediately.