Heat a pan over medium heat and add a few tablespoons of olive oil.
Sauté the minced garlic until fragrant, about 1 minute.
In a large bowl, combine the ground beef, chopped onion, egg, breadcrumbs, and milk. Mix gently until well combined.
Shape the mixture into 3cm meatballs.
Heat more oil in a large skillet over medium heat. Brown the meatballs in batches, 2 minutes per side; set aside.
In the same pan, add the sautéed garlic and a splash of water to deglaze (no alcohol). Add the crushed tomatoes, basil, oregano, salt, and black pepper.
Bring to a simmer; gently add the meatballs back into the sauce. Cover and cook for 30–40 minutes, stirring occasionally.
While the sauce is simmering, cook the spaghetti in salted boiling water until al dente, about 8–10 minutes. Drain and toss with a little Parmesan cheese.
Once the sauce is ready, skim any excess oil from the surface. Serve meatballs and sauce over spaghetti, garnished with parsley and a sprinkle of Parmesan.