For the bolognese sauce:
Wash and peel the carrot and onion, wash the celery and finely chop the vegetables. Dice the pancetta and put it in a large flame-proof casserole dish (preferably made of terracotta) and let it melt slowly. Add 3 tablespoons of oil and the chopped vegetables and let them sweat. Then add the ground beef and let it brown for about 10 minutes, then add the wine, stir and let it evaporate.
In the meantime, dilute the tomato paste in a little hot broth, pour it into the meat and mix well. Add salt, pepper and the chopped tomatoes. Cover and let it simmer gently for about 2 hours, stirring every so often and adding hot broth if it starts to dry up.
Towards the end of the cooking, add the milk to contrast the acidity of the tomato, mix and finish cooking.
Cook the pasta in plenty of boiling salted water, drain al dente and serve immediately with a lot of Bolognese sauce.