Spaghetti and Meatballs

Name: Spaghetti and Meatballs
Ingredients: 1 slice sandwich bread; 1/4 cup (60 milliliters) milk; 300 grams (11 ounces) lean ground beef; 2 Italian sausages (100 grams/3.5 ounces each), casings removed; 1 1/2 yellow onions, divided; 3 garlic cloves, divided; 1 egg; 3/4 cup (75 grams) finely grated Parmigiano-Reggiano cheese, plus more for serving; 3 tablespoons finely chopped parsley, divided; 2 teaspoons plus 1 tablespoon finely chopped oregano, divided; Kosher salt; Freshly ground black pepper; 2 tablespoons (30 milliliters) olive oil, divided; 1/3 cup tomato paste; 1 can (796 milliliters/27 ounces) crushed tomatoes; 500 grams (about 1 pound) dry spaghetti