Heat the butter on medium heat and add the onion, carrot, and celery. Cook for 15-20 minutes, stirring occasionally so that it does not burn.
Add the garlic, italian sausage, salt, pepper, and beef. Cook until the meat is mostly cooked.
Add the wine and stir. Allow the alcohol to cook out of the wine for about 3-5 minutes. Then, add your tomato paste and stir it in so that it is fully incorporated.
Add your tomato puree, beef broth, bay leaf, pinch of nutmeg and milk. Mix well and allow to simmer on low heat for 2-3 hours.