Make the meatballs. Combine all meatball ingredients in a large bowl and mix until just incorporated — don't overwork the meat. Roll into 1.5-inch balls (you should get about 16–18 meatballs).

Brown the meatballs. Heat a drizzle of olive oil in a large skillet or Dutch oven over medium-high heat. Sear meatballs for 2–3 minutes per side until browned. They don't need to be cooked through yet — just set aside once browned.

Build the sauce. In the same pan, reduce heat to medium and sauté the onion in olive oil for 4–5 minutes until softened. Add garlic and cook 1 minute more. Pour in both cans of tomatoes, sugar, basil, oregano, salt, and pepper. Stir to combine.

Simmer together. Nestle the browned meatballs into the sauce. Reduce heat to low, cover, and simmer for 20–25 minutes, stirring occasionally, until meatballs are cooked through.

Cook the pasta. Bring a large pot of heavily salted water to a boil. Cook spaghetti according to package directions until al dente. Reserve 1/2 cup of pasta water before draining.

Serve. Plate the spaghetti, spoon the sauce and meatballs on top, and finish with extra Parmesan and fresh parsley.