Step 1: Prepare the Meatballs

1. In a large mixing bowl, combine the beef mince, egg, torn white bread, minced garlic, chopped parsley, grated Parmigiano Reggiano cheese, salt, and pepper.
2. Mix everything thoroughly with your hands until well combined but not overworked.
3. Roll the mixture into small, uniform meatballs, about the size of a golf ball.

Step 2: Cook the Meatballs

1. Heat 1 tablespoon of olive oil in a large skillet over medium heat.
2. Place the meatballs in the skillet and cook for 8-10 minutes, turning occasionally, until golden brown on all sides and fully cooked through.
3. Remove the meatballs from the skillet and set them aside on a plate.

Step 3: Make the Tomato Sauce

1. In the same skillet, heat another tablespoon of olive oil over medium heat.
2. Add the diced onion and sauté until softened and translucent.
3. Stir in the chopped tomatoes, sugar, salt, and black pepper.
4. Reduce the heat and let the sauce simmer for 15-20 minutes, stirring occasionally, until thickened.

Step 4: Cook the Spaghetti

1. Bring a large pot of salted water to a boil.
2. Add the spaghetti and cook according to the package instructions until al dente.
3. Drain the spaghetti and set it aside. Reserve 1 cup of the pasta water in case you need to thin the sauce later.

Step 5: Combine Everything

1. Add the cooked meatballs back into the tomato sauce, stirring gently to coat them. Let them simmer in the sauce for 5 minutes to absorb the flavors.
2. Toss the spaghetti into the skillet with the sauce and meatballs. Mix gently to ensure the pasta is evenly coated.

Step 6: Serve

1. Serve the spaghetti and meatballs hot, garnished with extra grated Parmigiano Reggiano cheese and fresh parsley for a flavorful finish.