The caviar supper: late, small and extravagant on purpose

The caviar supper is not a dinner. It happens afterwards, when the play has come down or the long table has broken up, and two people want one more small, bright thing before the night ends. It is served late, it is served small, and it is deliberately more extravagant than it needs to be. That is the point of it. A gesture that could have been a nightcap becomes the thing that is remembered.

In this part of London it belongs most naturally in a suite, curtains open on Piccadilly and a tray sent up from the kitchen. It can also be held in a hotel bar, or at one of the rooms in Mayfair that make caviar their business. Wherever it happens, the rules are the same.

Caviar, strictly, is the salted roe of sturgeon and nothing else. The wild sturgeon of the Caspian and the Black Sea were fished close to extinction in the last century, and international trade in sturgeon products is now controlled under CITES, the convention on endangered species. Nearly all the caviar sold in London today is farmed, which is kinder to the fish and, many would argue, more consistent in the tin.

Every legal tin carries a CITES code on its label, and it is worth reading. It gives the species as a three letter code, the source, with C for captive bred, the country of origin, the year and the plant that processed it. A good merchant or a good hotel will be able to explain all of it without looking.

The names you will meet are few. Beluga, from the largest sturgeon, has the biggest and softest grains. Oscietra is nutty, its colour anywhere from golden to deep brown. Sevruga is smaller, finer and saltier. Kaluga, often sold as a hybrid, comes close to beluga in size. None is correct; each is a preference.

Caviar is simple food with strict manners. The manners exist to protect the flavour.

Champagne is the classic partner, and a dry one is best: a brut or extra brut, ideally a blanc de blancs, whose lightness and acidity clear the palate between spoonfuls. A vintage bottle is a lovely gesture, though hardly a necessity. Avoid anything sweet, which quarrels with the salt.

The older pairing is vodka, straight from the freezer in small chilled glasses, sharper and more austere, and some people will drink nothing else with it. If your companion prefers neither, a very cold, very dry white wine works, and so does sparkling water with a twist. The caviar is the extravagance. The glass should simply stay out of its way.

The suite is the natural home. Order through in-room dining before you go out, give a time, and the tray arrives when you do. Many of the grand hotels along Piccadilly and in Mayfair keep caviar on the late menu, or will find it with notice. If yours does not, the food hall at Fortnum's on Piccadilly sells it, and a good hotel will usually supply ice and plates for a tin brought in.

A hotel bar works too, particularly after the theatre, when the grand bars are quietening and a small plate with two glasses feels like a private celebration in a public room. What does not work is a busy restaurant at its peak. Caviar at nine in a crowded room is a menu item. Caviar at midnight, for two, is a supper.

Order ahead in every case. Kitchens can manage all of this at midnight, but they do it better when asked at ten.

There is a temptation, with caviar, to make it bigger: more tins, more bottles, more guests. Resist it. The supper is memorable because it is small, because it is late, and because it is shared by exactly two people who have already had a good evening and want to mark it. One tin, one bottle, two spoons. Anything more becomes a party, and a party is a different evening altogether.

It also suits the tempo of a long night. After a four hour dinner or a play, nobody wants another meal. A few spoonfuls, a cold glass and a quiet half hour are exactly enough, and they turn the end of the evening into its best moment.

Luna, one of our auburn companions, plans her evenings around a play and is at her sharpest once the curtain is down, when the supper becomes the second act. Stacy, tall and deadpan, prefers her supper after a comedy set, replaying the best lines between spoonfuls. Danielle, from our raven haired companions, will take a film apart slowly, one spoonful at a time.

A supper after the theatre fits the three hour booking at £1,500, or the full overnight engagement at £3,000, when the tray arrives and nobody needs to go anywhere afterwards. Tell Octavia the plan through booking and mention the caviar; she will propose a companion who enjoys it.