Make The Meatballs: In a large mixing bowl, combine the beef and pork, onion, garlic, seasonings like salt and pepper, basils, parsley, oregano, milk, egg, parmesan and breadcrumbs. Gently toss mixture and use fingertips to break the meat up, then mix with a wooden spoon until the mixture is fully combined. With greased hands, shape meatballs into even balls, around 1 1/2 inch (like golf ball size).
Cook The Meatballs: In a large frying pan/skillet, heat olive oil over medium heat. Add the meatballs in 2 batches and cook until golden brown on the bottom. Flip and cook the opposite side until golden brown. Remove from heat and set aside.
Make The Marinara Sauce: In the same pan, add butter then saute the onion and garlic until fragrant and light brown. Stir in crushed tomatoes and bay leaves then reduce the heat and allow to simmer for 10 minutes.
Add the meatballs to the sauce and allow to cook for another 20 minutes. Gently toss meatballs occasionally. Stir in chopped fresh basil and season with salt and pepper to taste.
Cook The Spaghetti: In a large boiling water, add some salt and cook spaghetti until al dente under package instructions. Drain the spaghetti then add to the pan with the meatballs and sauce and toss well to combine.
Transfer spaghetti and meatballs to a plate. Top with Parmesan cheese and fresh basil/green onion and serve immediately.