Tomato sauce

1. Combine tomatoes, butter, onion, salt and pepper in a large, wide pot. Bring to a boil and reduce to a gentle simmer. Cook until thickened and flavorful, about 45 minutes. As the sauce cooks, use a wooden spoon to gently smash open the tomatoes and break them down.
2. Remove from heat. Taste and add more salt or pepper if needed; discard onion. Use an immersion blender to blend the sauce smooth.

Giant meatballs

1. In a medium bowl, stir together eggs, milk, breadcrumbs, garlic, parsley, salt and pepper. Let sit 5 minutes to soften.
2. Add beef, pork, veal, and parmesan and gently mix until just combined (don’t overmix). Chill at least 15 minutes and up to 1 hour.
3. Divide mixture into 6 large meatballs (about 6 oz each). Roll into smooth balls, wetting your hands if needed.
4. Heat 1/4-inch olive oil in a large skillet over medium-high heat until shimmery, but not smoking. Fry meatballs in batches, cooking and turning every few minutes until all of the sides are golden brown and crisp. Drain on paper towels.
5. Transfer meatballs to sauce. Bring to a gentle simmer, cover, and cook until meatballs are cooked through, about 20 minutes, turning once or twice. Transfer meatballs to a large plate.
6. Cook spaghetti in a large pot of boiling salted water until al dente. Drain and toss with some of the leftover tomato sauce.
7. Divide pasta among 6 plates and top each with a giant meatball. Spoon extra sauce on top and serve, passing grated Parmesan.