Giant Meatballs with Ricotta

Name: Giant Meatballs with Ricotta
Ingredients: Olive oil, for baking sheet; 3 cups (½-inch pieces) crusty white Italian bread, crusts removed; 1 cup whole milk; 1 pound ground veal; 1 pound ground beef (80 percent lean); 1 pound ground pork; 1 large egg, lightly beaten; ½ medium onion, minced (about ¾ cup); ½ cup finely chopped flat-leaf parsley leaves; 1 teaspoon finely chopped fresh oregano leaves; 1 cup finely grated Parmigiano-Reggiano, plus more for serving; 1 ½ cups whole-milk fresh ricotta cheese; 1 teaspoon coarse salt; ¾ teaspoon freshly ground black pepper; 4 cups Marinara Sauce