Put oil and chopped onion in pot and cook over medium heat, stirring occasionally, until the onions are translucent.
Add celery and carrots and cook for 2 minutes.
Add beef, a large pinch of salt, and a few grindings of pepper. Cook until the beef is just browned.
Add milk and simmer, stirring frequently, until absorbed.
Add nutmeg and stir.
Add wine and simmer until evaporated.
Stir in tomatoes and when they begin to bubble, turn down to a low simmer.
Cook for 1 hour uncovered (or longer if desired). If sauce dries out while cooking, add 1/2 cup of water, but make sure to cook off so no water is left at the end.