Step 1: Sauté the Aromatics: Heat the olive oil in a large pot or deep skillet over medium heat. Add the chopped onion, carrot, and celery. Cook for about 8 to 10 minutes, stirring occasionally, until the vegetables are soft and the onion is translucent. Add the minced garlic and cook for another minute until fragrant.
Step 2: Brown the Ground Beef: Increase the heat to medium-high and add the ground beef to the pot. Use a wooden spoon to break the meat apart into small crumbles. Cook until the beef is thoroughly browned and no longer pink. Drain off any excess fat if necessary to keep the sauce from becoming too greasy.
Step 3: Deglaze and Season: If using red wine, pour it into the pot and stir well, scraping up any browned bits from the bottom. Let it simmer for 2 minutes until the liquid has reduced by half. Stir in the tomato paste and cook for 1 minute to mellow its acidity. Add the crushed tomatoes, beef stock, dried oregano, and the bay leaf.
Step 4: Simmer the Sauce: Bring the sauce to a gentle boil, then reduce the heat to low. Cover the pot partially with a lid and let it simmer for at least 45 minutes. If the sauce becomes too thick, you can add a splash of water or extra stock. Taste and season with salt and black pepper as needed.
Step 5: Cook the Pasta: While the sauce is finishing, bring a large pot of salted water to a boil. Add the spaghetti and cook according to the package instructions until “al dente” (firm to the bite). Reserve half a cup of the pasta water, then drain the rest.
Step 6: Combine and Serve: Remove the bay leaf from the sauce. For the best flavor, toss the cooked spaghetti directly into the sauce pot. Add a splash of the reserved pasta water to help the sauce cling to the noodles. Toss well and serve immediately with plenty of Parmesan cheese.