Remove the crust from the bread, peel the onion. Put bread, whole onions, salt, bay leaves and nutmeg in a pan. Pour in milk. Bring to a boil, then cook for 20 minutes under a lid over low heat.
Remove onion, bay leaf and nutmeg from the milk. Mash the bread with a fork. Add butter and cream, mix until smooth.
Pour the finished sauce into the gravy boat and serve.