Walk through the revolving doors, across the lobby and then down the gently sloping staircases to the basement of the Ritz Hotel. Now turn left and go through the main kitchen, with the ancient copper frying pans on the wall. Pass the head chef's office and walk down twisting corridors until you reach a smallish box of a room dominated by a large square island with a marble top.
Here, on a sticky day in late August, 16 chefs are standing to attention along the back wall, their whites snow-blindingly bright. "Now listen," says John Williams, the executive head chef of the Ritz for the past nine years. "We may be doing this by hand, but I want as little ingredients on the floor as possible."
They laugh; he laughs. And as well they might, because today this little platoon of chefs will combine a third of a ton of ingredients on that 2in-thick piece of marble in front of them. In a couple of hours, they will make 2,000 Christmas puddings. Welcome to the big Ritz mix-up.
It begins with raisins; 40kg of them, tumbling on to the table in one great dark wave. Hands dart in. Boxes of dry ingredients are upturned. Thick and fast it comes: 40kg of sultanas, 38.5kg of currants, 7kg of glacé cherries, 8kg of grated carrots, 2kg of crystallised ginger. More and more is piled on the table until there is a small mountain range of mottled brown ingredients before us. "Ross, start adding the alcohol," Williams says in an accent that manages to be both clipped and still unmistakably Tyneside, where he was born. "And straighten your hat, too," he adds, playfully.
The wet ingredients rain down on to the table. Into the mix goes 16 bottles of Guinness, 1.3l of cognac, 13.5 bottles of bitter, 1.3l of Madeira, the same again of sherry and nearly 2l of rum. Fumes drift up lazily into the low-ceilinged room. It smells, well, it smells of Christmas. But there's no time to savour it; 162 eggs need to be dragged through the entirety of the mix.
Hands twist in and out like vines, swirling, turning, grabbing and pulling. The jumble of arms remind me of a windmill; over, over, over again. Now, one of the older chefs has picked up a long oar-like mixing board. He digs it in, heaves it up, turns it over and down comes a snowstorm of currants.
At this point, I find myself wondering why the dowager duchess of hotels, founded by César Ritz in 1906, has to mix its Christmas puddings by hand? Would not a Kenwood suffice? Isn't this just the fetishisation of an outmoded culinary technique? Williams smiles. "No," he says. "It's because we don't have a mixer big enough."
Maybe that shouldn't be a surprise – 2,000 is, by anyone's standard, a lot puddings. It seems, in fact, faintly absurd, given that they are on sale for only the 25 days leading to Christmas Day. According to Williams, however, they sell out faster than Louboutins at the Harrods sale. Nearly 1,800 will be served in the dining room at the Ritz during the season (220 are sold on Christmas Day alone) and a further 200 are on sale, for £35 a pop, from the "Christmas concierge" in the hotel lobby. At the moment, though, we're a long way off that point. Thirty-six hands are still working on the mixture. The arms keep rolling. "Is it getting harder?" asks Williams. "Oh, easier, chef, easier," comes the not-so-serious reply. By now, Daisy Whitbread, the head pastry chef, one of the higher divinities in the Ritz kitchen, has arrived and joins the fray. As the orange peel flies, I ask her if she enjoys the day? Isn't it all, well, a bit of a palaver? It isn't easy, she says, but it's tradition, though only a five-year-old one. "Besides, it brings the kitchen together. It's about building a team as much as anything else," she says. Ross Blount, one of the stronger arms in the mix, nods in agreement. "Aside from anything else, it's a good workout," he says.
If this all seems a little antique, that's because in some senses it is. As you watch the kitchen staff interact, it brings to mind a parade ground: they are like a company of soldiers. Which is just as Williams wants it, as his kitchen follows the Brigade de Cuisine structure pioneered by Escoffier in the late 19th century. At the apex is Williams himself, then comes the premier sous chef and pastry chef Daisy, and below them, seven more sous chefs, each with a full "brigade" of chefs below them toiling on sandwiches, butchery, larder, vegetables, sauces, fish and breakfast. The advantage of this system is that everyone knows what they're doing; what the metric of success for their work is. And on the evidence before me, it works very well indeed – there are, I count, only nine currants on the floor.
As they begin to put handfuls of mixture into the plastic bowls, which will be the puddings' homes for the next 122 days, I ask about the recipe. Is it a museum piece? A closely guarded Ritz secret? Not quite, Williams says. The recipe they are following today is only three years old and is simply a souped-up version of the one your granny probably used. The main difference is the ingredients. "We use the best produce we can. Particularly important is the quality of the candied fruit and the carrot. The fruit gives texture and that is what a good Christmas pudding is all about. The carrot, too, is essential – it ensures everything stays nice and moist."
Certainly when I try a cooked version, hot, steamed and flambéed in cognac, it's a model of moistness. Rich as Croesus, too. And reassuringly alcoholic. One can see why, for those who can afford it, these puddings are a Christmas Day must. "We get the same people coming in to buy them each year. One guest had one sent out to LA last year. Not by courier, either. It went on a plane," he says. If I was rich and lived the other side of the world, I might do the same, too.
If Christmas pudding is the taste of the season, then the Ritz kitchen must be the most Christmassy place in the country.
The good pud guide: other festive desserts
Don't fancy the full bells-and-whistle pudding after all that turkey? Try out these alternatives
* The Heston from Waitrose Strawberry and Lychee Frozen Gateau (£12.99) is as light as a fashion model. It is made from layers of lychee mousse, lemon and strawberry confit, rose water mousse, nut and white chocolate feuilletine, almond sponge, alpine strawberries, Charlotte sponge and lychee liqueur. It's full of contrasting textures and looks brilliant as a table centrepiece.
* As part of its new Italian range, Marks & Spencer is now selling a classic Torta Tre Monti (£6.99) which is made in San Marino by La Serenissima Company. The simple dessert is composed of five layers of wafer, between which is spread a thick layer of chocolate and hazelnut cream, and then topped with dark chocolate.
* The Christmas Tree yule log on sale to guests at one of Paris's finest hotels (€16 per slice), Le Meurice, is probably the best non-pudding Christmas dessert there is. It is made by the hotel's pastry chef, Cedric Grolet, and consists of a citrus shortbread base, topped with lemon cream, marmalade and cedar mousse, and then covered with white chocolate. A divine dessert – and one that won't put you to sleep after two mouthfuls.