This week, we ought to spare a thought for vegetarians at Christmas. The phrase ‘raw deal’ comes to mind whenever I think of the strain the festive season must put those of a veggie persuasion under at this time of year.

Because, food-wise, it’s a pretty relentless toboggan ride through Meatville all the way until January, when we all pat our stomachs and crack open the bags of salad. From late October, it’s hard to move for ginormous turkeys, straining tubes of sausage meat or slabs of pâté.

The supermarket shelves resemble vast dormitories of pigs in blankets and snoozing chipolatas. There are huge juicy hams, salamis and terrines, and mountains of bacon. It really must be pretty hard going for the non-carnivorous at this time of year.

A good nut roast is truly a thing of beauty, but sadly there aren’t many about in the wild.

So, with this in mind, and, having had a bit of a brainstorm one evening, I decided upon creating a dish that can take every bit as much of the Christmas Lunch spotlight; a wonderful, golden pie, filled with rich, creamy potato, soft, golden onions and tangy molten cheese.

Glazed with a dab of Marmite to add a deeply savoury kick, we serve this in big wedges alongside our vegetables of choice and a simple velouté sauce made with vegetable stock, a splash of white wine and a hefty slug of truffle oil to add a decadent touch and a magical aroma.

A jar of Marmite

Essentially we’re making a classic gratin Dauphinois, that super-rich concoction of potatoes and cream from the mountains of France, then baking it in a pie, but with the extra flavours of slowly-caramelised onions and a good tangy cheese. The cheese choice is entirely yours – you could go for a more traditional Gruyère, Cheddar, or even a tangy blue, but I find the acidity and twang of a tasty-style Lancashire fits the bill perfectly here.

You can make everything a day in advance, or longer if you freeze the pie in its raw state.

If you don’t have enough guests to justify making such a big pie, you could try making individual pithiviers with two discs of puff pastry moulded around a cylinder of gratin, or even make simple pasties with a rough puff or shortcrust, filled exactly the same way.

A note on the truffle oil; the Terre Nostre brand of truffle oil is by far the best I’ve come across – strong, and deeply aromatic. t’s worth having a bottle on the shelf for any number of reasons – drizzling over the Sunday roast of beef or chicken, or boosting the humble cheese toastie.

It’s great on pasta and wonderful with roasted root vegetables. Well worth splurging on a bottle, and this brand is great because it’s far more intense than any other supermarket-stocked brands I have tried.

It can be found locally at the large supermarket that used to be Hillards. Mum’s the word. So please, do try this simple, yet luxurious dish – don’t let the veggies keep this one to themselves!

For the pastry:

250g plain flour

pinch of Maldon salt

110g butter, diced

2 free-range egg yolks

4-6 tbsp ice-cold water

For the potato filling:

6 large baking potatoes

600ml double cream

200ml milk

240g tangy Lancashire Cheese, finely grated

Lancashire cheese

2 onions, peeled and finely sliced

A little salted butter

A little freshly-chopped thyme

A little freshly-chopped curly parsley

For the truffled velouté sauce:

40g butter

40g plain flour

70ml dry white wine

500ml hot vegetable stock (I used my favourite Marigold bouillon)

1 tbsp truffle oil

A little freshly-chopped curly parsley

Extras:

1 loose-bottom tart case or pie tin, roughly 25cm x 6cm high

1 teaspoon Marmite

2 free-range egg yolks

Method:

First, make the pastry; in a food processor, or by hand, mix the butter into the flour until the mixture resembles breadcrumbs, then, with the motor still running, add the egg yolks, then the water, drop by drop, until the dough just starts to come together. Remove from the bowl and knead together quickly into a smooth ball of dough. Chill this for about 30 minutes. Remove a third, with which to make the lid, wrap this in clingfilm and chill. Roll out the remaining pastry on a floured surface to the thickness of a pound coin, and carefully line the tart case, pushing the pastry to the edges. Leave the excess pastry around the top to attach to the lid. Chill until required.

Now, let’s make the gratin. Butter a suitable deep baking dish or casserole (mine was about 25cm wide by 10cm high) Peel the potatoes and slice as thinly as possible, or use a mandolin. Do not put them in water, as we need the starch to help thicken the gratin. Warm the cream and milk in a wide pan until just bubbling, and tip in the potato slices. Cook gently, turning occasionally, until you can just get the point of a knife through the potato. Remove the potato slices and drain in a colander, reserving all the cream. When drained, return the cream to the pan and bring to the boil. Reduce the heat a little and bubble until reduced by about half. It will be desperate to catch on the base of the pan, so use a spatula or whisk to prevent this. Remove from the heat, and whisk in the parsley and thyme. Check the seasoning too. Set the oven to 160ºC / Gas 4. Carefully layer up the potato slices in the buttered dish, and pour over the thickened cream. It should just come to the level of the potatoes. If there’s too much, don’t add all of it – we need the pie filling to be moist but not sloppy. Cover with a lid or foil, and bake for 45 minutes until soft.

As the gratin cooks, sweat the onions gently in a little butter with a pinch of salt, under a disc of baking paper, stirring occasionally, until they are very soft and golden. It’s essential we cook the onions for at least 40 minutes, as any lingering acidity will split the cream in the pie (that’s why many gratins using raw onion look like cottage cheese). Drain the onions in a sieve to remove any excess butter. Remove the gratin from the oven and chill completely. Grate the cheese. When the gratin is completely cold, begin layering up slices of creamy potato with the onions and sprinkles of cheese, filling the pie completely and evenly.

Roll out the lid pastry. Make the glaze by whisking the Marmite into the egg yolks and brush a little all around the rim of the pie pastry. Press the lid pastry down, and make sure it’s well attached all the way around. Trim away any excess, and crimp together with a fork or by hand. Glaze the top of the pie. Refrigerate for about half an hour.

Heat the oven to 200ºC / Gas 6. Bake the pie for about 30 minutes, or until the pastry is well set and nicely golden all over. Remove from the oven and allow to cool slightly before serving.

As the pie bakes, make the velouté sauce; melt the butter in a saucepan, and when sizzling, add the flour and whisk for a minute or so. Slowly whisk in the hot stock, avoiding lumps, and add the wine. Bring to the boil and simmer for 10 minutes. Add the truffle oil and pass into another pan through a fine sieve to obtain a smooth, silky sauce. Whisk in the parsley and keep warm until you’re ready to serve.

The pie is best served in hearty wedges with a good selection of vegetables and plenty of the vegetable velouté sauce.