Combine ground beef, ground pork, finely chopped onion, fresh breadcrumbs, milk, egg, finely chopped green pepper, chopped fresh parsley, and crushed garlic in a large bowl.

Season the mixture with salt and pepper.

Roll the mixture into 24 meatballs.

Heat 1/4 cup olive oil in a large skillet over medium-high heat.

Cook the meatballs in batches for 5 minutes, or until browned on all sides.

Drain the browned meatballs on paper towels.

Heat the remaining 1 tablespoon olive oil in a large saucepan over medium heat.

Add the remaining crushed garlic and cook, stirring, until fragrant.

Pour in the dry white wine, diced tomatoes, tomato paste, and chicken stock. Bring to a boil.

Reduce heat to low, cover the saucepan, and cook for 15 minutes.

Add the browned meatballs to the sauce, simmer, covered, for 25 minutes.

Stir in the remaining chopped fresh parsley. Season to taste.

Meanwhile, cook the spaghetti in a large saucepan of boiling water according to package directions.

Drain the cooked spaghetti.

Serve the spaghetti topped with the meatballs and sauce.

Garnish with fresh curly parsley sprigs.