In a large bowl combine the ground beef, ground pork, softened breadcrumbs (with any unabsorbed milk), egg, grated Parmesan, minced garlic, chopped parsley, dried oregano, salt, and black pepper. Use your hands or a spoon to gently mix until just combined — avoid overworking or the meatballs will be tough.

Form meatballs

Portion the mixture into evenly sized meatballs, about 1 1/4 inches in diameter (roughly 1.5 oz / 45 g each) to yield about 18–20 meatballs. Roll gently between your palms to form smooth balls; avoid compacting them too tightly.

Brown meatballs

Heat 2 tablespoons olive oil in a large skillet over medium-high heat. Working in batches to avoid crowding, add meatballs and brown on all sides, about 6–8 minutes total per batch. They do not need to be fully cooked through — just nicely browned. Transfer browned meatballs to a plate lined with paper towels.

Tomato Sauce

Sauté aromatics

In a large heavy-bottomed pot or deep skillet, heat 1 tablespoon extra-virgin olive oil over medium heat. Add the finely chopped onion and cook, stirring occasionally, until translucent and softened, about 5–6 minutes. Add 3 teaspoons minced garlic and cook 30–45 seconds until fragrant, taking care not to brown it.

Build the sauce

Stir in 2 tablespoons tomato paste and cook 1 minute to deepen the flavor. Add the crushed tomatoes, dried basil, dried oregano, sugar (if using), 1 teaspoon salt, 1/2 teaspoon black pepper, and 1/2 cup water or chicken broth. Stir to combine and bring the mixture to a gentle simmer.

Simmer with meatballs

Carefully add the browned meatballs to the simmering sauce, nestling them so they are partially submerged. Reduce heat to low, cover partially, and simmer gently for 20–25 minutes, stirring occasionally and spooning sauce over the meatballs to ensure even cooking. Check one meatball with a thermometer — it should reach 160°F (71°C) for beef/pork. If sauce becomes too thick, add a splash of water.

Pasta & Finish

Cook spaghetti

About 10 minutes before the meatballs are done, bring a large pot of water to a rolling boil. Add 1 tablespoon salt. Add 12 oz dry spaghetti and cook according to package instructions until just al dente (usually 8–10 minutes). Reserve 1/2 cup of the pasta cooking water, then drain the spaghetti.

Combine pasta and sauce (optional)

If you prefer to finish the pasta in the sauce, add the drained spaghetti to the pot with the simmering sauce and meatballs over low heat. Toss gently to coat, adding reserved pasta water a few tablespoons at a time as needed to loosen the sauce and help it cling to the pasta. Cook together 1–2 minutes until integrated.

Plate and garnish

Divide spaghetti among 4 warmed plates (serves 4). Top with meatballs and extra sauce. Sprinkle with grated Parmesan and torn fresh basil leaves. Serve immediately.