Polpette al Sugo (Meatballs in Tomato Sauce)

Ingredients

• 1 pound (450g) ground beef
• 1/2 pound (225g) ground pork (optional; you can use all beef if preferred)
• 1/2 cup breadcrumbs
• 1/4 cup grated Parmesan cheese
• 1/4 cup milk
• 1 egg, beaten
• 2 cloves garlic, minced
• 2 tablespoons fresh parsley, chopped
• Salt
• freshly ground black pepper
• 2 tablespoons olive oil
• 1 onion, finely chopped
• 1 can (28 ounces) crushed tomatoes
• 1 teaspoon dried oregano
• 1 bay leaf
• Fresh basil leaves, for garnish