Chef John Williams is in his glass office in the middle of the kitchens that sprawl beneath the Barclay Brothers-owned Ritz hotel. It's only a few hours before lunch service. Veal stock simmers gently in sink-sized basins. Raspberries are painstakingly sliced in half by pastry chefs. Potato is whipped to oblivion.
In his office, Williams, 60, is almost leaping out of his chair with excitement. He motions to his PA. "Ask one of the lads to get me the smoke gun!" he says, and a few moments later a sous chef enters with the gadget, along with a fine-bone-china cloche and plate.
The younger chef then pumps woodchip-scented smoke underneath the cloche, the dome is removed and - pouffe! - a scented cloud floats up from the plate. This is how they do quails' eggs at the Ritz, the smoke gently flavouring the eggs before its release.
It's these "little moments of theatre" that Williams is keen to demonstrate are back at the restaurant, which won its first Michelin star in 2016. He is an enthusiastic proponent of haute cuisine: fine sauces based on stock and butter, showers of truffle, wild salmon and langoustine.
His passion for Gallic cookery is enunciated in Geordie vowels only slightly clipped by decades working in London's restaurant scene. "It's classic, but it's not old-fashioned," is how he describes the contemporary Ritz style of cookery. "It's actually very relevant to the modern diner, and as good as anything you'll get in London now."
Auguste Escoffier, the godfather of French cuisine, was once a consultant to César Ritz, founder of the hotel back in May 1906, and Williams is an Escoffier superfan. Just as well: tradition is palpable here, and for the past 14 years as executive chef Williams has toiled to make the restaurant's food match up to its rich setting - the glorious Palm Court tea room is as grandiose as a Cecil Beaton backdrop.
But most of all, his mission has been to send out food that could do justice to the Ritz Restaurant, a vast apricot-coloured marble and gilt dining room, with floor-to-ceiling windows overlooking Green Park. Mrs Thatcher had a favourite corner table here, and Williams has cooked for the Queen and numerous presidents. (Who of his famous diners has the best palate? "Rod Stewart. Very particular.")
So it's surprising that Williams's latest project is a recipe book. Has he modified the recipes for the home cook? "Everybody told me, it's got to be accessible. But hang on: the Ritz is not accessible! My idea was to put in certain things that somebody could say, 'Ah, I could make that'. But there's also an element of showing, 'This is what we do at the Ritz.'"
The Ritz London: The Cookbook is part technical recipe book, part memoir. There are Williams's memories of growing up in South Shields, the son of a trawlerman, who accompanied his mother on shopping trips to the butcher and developed a precocious taste for tripe and Jersey Royals. As for the recipes, certain classics are within the range of the dinner-party cook (salt-baked celeriac, for instance, or venison Wellington, the latter a dish Williams says he makes himself for guests at home).
However, he'll admit that the inclusion of dishes such as canard à la presse - in which a flash-roasted duck is squished at the diner's table in a special duck press, the resultant blood thickening in a rich sauce - is more about showing off his restaurant's repertoire than offering a practical guide for amateurs. I mean, where can I get a duck press?
"You can commission one from Christofle, the famous French silver maker, but it wouldn't cost less than £16,000." He grins. It would be far more economical, then, simply to dine at the Ritz.
The Ritz London: The Cookbook (Mitchell Beazley, £30), with photography by John Carey, will be published on 6 September
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