1. Preheat the oven to 220°C/ gas mark 7. Put the salt and caraway seeds into a bowl, crush or grate in the garlic, mix everything together and rub the pork hocks with this mixture, getting well into the slits of the scored rind.
2. Peel the onions, slice into rounds and make a bed or platform of them in a roasting tin. Sit the knuckles on this onion layer and cook them in the hot oven for half an hour.
3. Take the tin out of the oven and quickly arrange the apples and potatoes around the hocks, then carefully pour half the beer (250ml) over, aiming for the hocks so they are basted as the liquid pours into the tin. Put back in the oven, turning this down to 170°C/ gas mark 3 and leave to cook at this lower temperature for two hours.
4. Turn the oven up again to 220°C/ gas mark 7, baste the hocks with the rest of the beer, and leave to cook at the higher temperature for another 30 minutes.
5. Take the tin out of the oven and transfer the apples and potatoes to a warmed dish. Lift the hocks onto a carving board, leaving the onion and juices in the tin.
6. Now put the tin on the hob over a medium heat and add 500ml boiling water, stirring to de-glaze the pan to make a gravy.
Take the crackling off the pork and break into pieces, pull apart or carve the meat and serve with the apples, potatoes, gravy and some German mustard.
Make ahead note:
The pork and onions can be put in roasting tin up to one day ahead. Cover with clingfilm and refrigerate.
Just before cooking, rub with the salt, caraway and garlic and cook as directed.
Making leftovers right:
Leftover pork can be stored in the fridge, tightly wrapped in foil, for up to three days. Eat it cold or reheat gently in a saucepan with leftover gravy, until piping hot. You should store any leftover gravy in a separate airtight container in the fridge for one to two days. Leftover pork can be frozen for up to two months, tightly wrapped in foil, then defrosted overnight in the fridge.
Recipe from Nigella: Kitchen by Nigella Lawson (published by Chatto & Windus).