Place a large pot on medium heat. Add olive oil and allow it to warm up slowly. The oil should shimmer slightly. This step prepares the pot for cooking the meat and vegetables.

Add ground beef and Italian sausage to the pot. Break the meat into small pieces using a wooden spoon. Cook until the meat becomes brown and fully cooked.

Add the chopped onion into the cooked meat mixture. Stir well and cook for about five minutes. The onions should soften and become slightly golden.

Add the minced garlic to the pot. Stir gently for one minute. Garlic cooks quickly, so avoid burning it. This step adds a deep aroma to the sauce.

Stir in the tomato paste and mix it with the meat. Let it cook for two minutes. This deepens the tomato flavor and makes the sauce richer.

Add crushed tomatoes and tomato sauce to the pot. Stir everything together slowly. The mixture will start forming a thick and rich base for the spaghetti sauce.

Add salt, black pepper, oregano, basil, sugar, and red pepper flakes. Mix the spices carefully into the sauce. These seasonings create the classic Italian flavor.

Pour in the water or beef broth. Stir gently until the sauce becomes smooth. The liquid helps the sauce simmer slowly without becoming too thick.

Lower the heat and let the sauce simmer uncovered. Stir every 10–15 minutes. Slow cooking allows the flavors to blend and deepen beautifully.

After about one hour, taste the sauce. Add extra salt, herbs, or sugar if needed. Small adjustments help balance the final flavor.

While the sauce finishes cooking, boil spaghetti noodles in salted water. Cook according to the package instructions. Drain and set aside.

Place warm spaghetti on a plate. Ladle the rich sauce over the pasta. Top with fresh parsley and grated Parmesan cheese.