Saute onions and garlic in pot with some salt until soft and translucent.
Add red wine and bring to a boil.
Add both cans tomatoes, Italian seasoning, pepper and crushed red pepper.
Blend sauce with immersion blender (optional).
Simmer, stirring occasionally, for at least one hour. Add water if sauce gets too thick.
Taste, adjust seasoning and add water as necessary. If sauce is too acidic, add a teaspoon at a time of sugar to balance.
About 10 minutes before serving, add chopped parsley and butter to sauce
Add reserved pasta water (below) as needed for desired consistency.
Meatballs
Combine egg, garlic, beef, pork, salt, pepper, Parmesan cheese, bread crumbs, and Italian parsley in large mixing bowl, mix by hand until incorporated (do not overmix)
Rest covered for at least 30 minutes (can do longer, place in refrigerator as needed)
Preheat pan (cast iron recommended) on medium high heat. While pan is preheating, ortion into meatballs, approximately 1 inch in diameter, will net around 25 meatballs.
Add canola oil to pan. Working in batches as needed, saute meatballs on all sides until browned but not cooked through, transfer to tomato sauce to finish cooking.
Spaghetti
Bring large pot of salted water to a boil
Add spaghetti and olive oil and cook, stirring occasionally, until spaghetti is done, approximately 10-11 minutes.
Drain pasta, reserving some of the pasta water (1/2 cup or so).
Add spaghetti to plate, add some sauce and 3-4 meatballs, top with grated Parmigiano Reggiano