Heat butter and olive oil in a pan on medium heat. Sauté onions, carrots, and celery.
Stir for 7 minutes until they are soft.
Add minced meat and press until it becomes small chunks—season with salt. Stir again for 3 minutes until the meat colour changes. Add wine.
Replace the pan lid and reduce the heat. Leave it for 4 minutes. Remove the pan lid and add milk and nutmeg powder. Stir. Replace the lid again. Leave it for 4 minutes.
Add tomato sauce and stir well until done. Remove from the heat.
Serve with spaghetti