Potato Gratin with Ham & Cheese

• 1.2 kgpotatoes, peeled and thinly sliced (3mm)
• 1small onion, thinly sliced
• 6 gfresh thyme leaves (optional) (optional)
• 200 gcooked ham, sliced or chopped
• 40 gplain flour
• Salt and black pepper, to taste
• 600 mlwhole milk, warmed
• 40 gbutter
• 200 ggrated cheddar (reserve some for the top)
• 1 tspDijon mustard
• ¼ tspground nutmeg
• 15 gflat-leaf parsley, chopped
• 1lemon, zest and juice

Method

1. 1Heat the oven to 180°C (fan 160°C) and use a little of the measured butter to grease a 20x30cm ovenproof dish. Slice the potatoes a steady 3mm thick; any thicker and they won't cook through in the time the top takes to brown.
2. 2Melt the remaining butter in a saucepan over a medium heat until foaming, stir in the flour and cook for 1 minute until it smells biscuity; that's the raw flour cooking out. Gradually whisk in the warmed milk a splash at a time, letting each addition come together before the next, then simmer for 3–4 minutes, stirring, until thick enough to coat the back of a spoon.
3. 3Off the heat, stir in 150 g of the grated cheddar, the Dijon and the nutmeg until glossy. Season the sauce generously with salt and pepper, then taste it; it should taste a touch over-seasoned on the spoon, because the potatoes are bland and will soak it up.
4. 4Layer a third of the potatoes across the base of the dish, season the layer with a pinch of salt and pepper, scatter over half the onion and half the ham, then spoon over a little sauce so every slice is properly coated. Repeat with another seasoned layer and finish with a neat top layer of potatoes.
5. 5Pour the remaining sauce over the top so it seeps between the slices; it should come close to the top of the potatoes. Scatter over the reserved 50 g cheddar and the thyme leaves if using.
6. 6Cover loosely with foil and bake for 45 minutes, then uncover and bake for a further 15 minutes until the top is deeply golden and bubbling at the edges and a skewer slides through the potatoes with no resistance. If the top is pale, push it under a hot grill for 2 minutes; watch it, cheese goes from golden to scorched fast.
7. 7Rest for 10 minutes so the layers settle and slice cleanly; straight from the oven it slumps, rested it holds.
8. 8Mix the chopped parsley with the lemon zest and juice. Spoon a little over each portion just before serving to brighten the rich gratin.

Per serving

kcal

733

protein

35.1g

fibre

8.3g

carbs

75.5g

fat

34g