Heat the olive oil in a large, heavy-bottomed pot over medium heat. Add the onions, garlic, carrots, and celery, and cook until the vegetables are soft and translucent, about 5-7 minutes.
Increase the heat to medium-high and add the ground beef and pork. Cook, breaking up the meat with a wooden spoon, until browned and cooked through, about 10-12 minutes.
Pour in the red wine and let it simmer until reduced by half, which will take around 5 minutes.
Stir in the crushed tomatoes, tomato paste, basil, oregano, bay leaves, and sugar. Season with salt and pepper.
Bring the sauce to a gentle simmer, then reduce the heat to low. Cover and let it cook for at least 2 hours, stirring occasionally. For an even richer flavor, you can cook it longer, up to 4 hours if time allows.
During the last 30 minutes of cooking, remove the lid and stir in the whole milk. Continue to simmer until the sauce is thick and creamy.
Serve the bolognese sauce over your favorite cooked pasta and sprinkle with grated Parmesan cheese.
Prep time: 20 minutes | Cook time: 2-4 hours | Total time: 2 hours 20 minutes to 4 hours 20 minutes
Servings: 8-10Cooking Time: 2-4 hoursTotal Time: 2 hours 20 minutes to 4 hours 20 minutesKcal: Approximately 600 kcal per serving