- Pour the milk into a large saucepan and add the onion halves, spices and herbs.
- Bring the milk slowly to the boil then immediately remove from the heat and set aside to infuse for at least an hour (it will happily sit for a few hours if making ahead).
- When ready to serve, strain the milk through a sieve into a clean saucepan, discarding the onions, spices and herbs. Place over a medium heat and gently warm through before stirring in the breadcrumbs.
- Add the butter and continue to stir over the heat for a few minutes until the sauce thickens. Season to taste with sea salt, freshly ground black pepper and freshly grated nutmeg.
- Transfer to a warmed serving dish and grate over a final dusting of nutmeg to finish.
Tips: Traditionally the onion is studded with the cloves before adding to the milk – you can do this if you want but it works just as well all thrown in the pan together.