1. Finely chop the garlic and onion, then dice the carrot and celery into small pieces (remove the main celery veins).
2. Heat the oil in a large enough pot. Sauté the garlic, onion, carrot, and celery over low heat for 5 minutes, stirring.
3. Increase the heat, then add the beef. Brown it and stir to prevent the meat from forming large clumps.
4. Add the broth, red wine, roughly chopped tomatoes, sugar, and chopped parsley. Bring to a boil.
5. Reduce the heat and simmer covered for 1 to 1.5 hours, allowing the wine to evaporate.
6. Cook the spaghetti, then place them in a dish.
7. Add the Bolognese sauce.