2 1/4 cups (about 6 ounces) panko bread crumbs
1 1/2 cups buttermilk (see note)
3 large eggs , lightly beaten
2 pounds 85 percent lean ground beef
1 pound ground pork
6 ounces thinly sliced prosciutto , chopped fine
3 ounces Parmesan cheese , grated (about 1 1/2 cups)
6 tablespoons minced fresh parsley leaves
3 medium garlic cloves , minced or pressed through garlic press (about 1 tablespoon)
1 1/2 teaspoons powdered gelatin , dissolved in 3 tablespoons cold water
Table salt and ground black pepper
3 tablespoons extra-virgin olive oil
1 1/2 cups grated onion from 1 to 2 onions (see note)
6 medium garlic cloves , minced or pressed through garlic press (about 2 tablespoons)
1/2 teaspoon red pepper flakes
1 teaspoon dried oregano
6 cups tomato juice (bottled)
3 (28-ounce) cans crushed tomatoes
6 tablespoons dry white wine
Table salt and ground black pepper
3 pounds spaghetti
1/2 cup minced fresh basil leaves
3 tablespoons minced fresh parsley leaves
Granulated sugar
Parmesan cheese , grated, for serving
1. FOR THE MEATBALLS: Place wire racks in 2 foil-lined rimmed baking sheets. Adjust oven racks to lower-middle and upper-middle positions and heat oven to 450 degrees. Combine bread crumbs and buttermilk in large bowl and let sit, mashing occasionally with fork, until smooth paste forms, about 10 minutes.
2. Add eggs, beef, pork, prosciutto, Parmesan, parsley, garlic, gelatin mixture, 11/2 teaspoons salt, and 1/2 teaspoon pepper to bread-crumb mixture. Using hands, gently mix until thoroughly combined. Lightly form about ¼ cup mixture into 2-inch round meatball (about 2 ounces); repeat with remaining mixture to form approximately 40 meatballs.
3. Spray wire racks with nonstick cooking spray and place meatballs, evenly spaced, on racks; roast until browned, about 30 minutes, rotating trays from front to back and top to bottom halfway through.
4. FOR THE SAUCE: While meatballs roast, heat olive oil in large Dutch oven over medium heat until shimmering. Add onion and cook, stirring occasionally, until softened and golden around edges, 6 to 8 minutes. Add garlic, red pepper flakes, and oregano; cook, stirring frequently, until fragrant, about 30 seconds. Stir in tomato juice, crushed tomatoes, wine, 1½ teaspoons salt, and pepper to taste. Increase heat to medium-high and bring to simmer. Reduce heat to medium-low and simmer until slightly thickened, about 15 minutes.
5. Remove meatballs from oven and lower oven temperature to 300 degrees. Gently add meatballs to sauce, cover pot, and place in oven. Cook until meatballs are firm and sauce has thickened, about 1 hour.
6. Meanwhile, bring 10 quarts water to boil in 12-quart pot. Add pasta and 2 tablespoons salt to boiling water; cook until al dente. Drain pasta and return it to cooking pot.
7. TO SERVE: Stir basil and parsley into sauce and adjust seasoning with sugar, salt, and pepper. Toss pasta with 1½ cups sauce until lightly coated. Serve pasta, passing meatballs, remaining sauce, and grated Parmesan separately.