Ham and Leek Gratin

Our Christmas ham (York bone-in from www.dukeshillham.co.uk) ordered with lots of family meals in mind is still plentiful and this gratin was inspired by chunky trimmings. Other ham could be used but chunky pieces rather than thin slices are preferable for this recipe. York ham is dry cured from large white pigs and is saltier and firmer than most hams, so if using, take it easy on the salt.

Serves 2, generously
Prep: 20 min
Cook: 45 min

1 onion
40g butter
½ tbsp vegetable oil
300g trimmed leeks
few sprigs thyme
1 heaped tbsp flour
1 tsp Dijon mustard
splash white wine
150ml chicken or vegetable stock
150ml milk
200g chunky scraps of ham
3 tbsp finely grated Parmesan
3 tbsp fine breadcrumbs

Halve, peel and finely chop the onion. Melt the butter in the olive oil and stir in the onion with a generous pinch salt. Adjust the heat so the onion softens without browning, stirring often until slippery soft. Meanwhile, slice the leeks in 1 cm rings. Agitate in a bowl of water to loosen any grit then drain. Strip the thyme leaves from the stalks and chop. Stir the leeks into the softened almost cooked onion. Cover and cook for 5 minutes, stir, re-cover and cook for a further 5 minutes or until the leeks is floppy and tender. Sift the flour over the top of the leeks and stir briskly to disperse. Stir in the mustard and then the white wine, stirring constantly before adding the stock. Keep stirring, letting it bubble up to make a thick sauce. Add the milk, stirring steadily, adjusting the heat as necessary, so everything cooks gently. Fold in the chunks of ham, then tip the mixture into a gratin dish – mine was 30 x 16 x 6cm. Gently flatten the mix and leave to cool. Mix cheese and breadcrumbs and scatter over the top. Bake now or later, the dish placed on a roasting sheet to catch any spillage, at 200C/gas mark 6 for about 30 minutes, checking after 20, until the top is crusty and golden.