Koffmann's, Knightsbridge

For those of us afflicted by the increasingly-common condition known as Restaurant Obsessive Disorder - symptoms of which include poring over online menus late at night, booking tables at new restaurants the minute phonelines open, and cataloguing everything we eat in words and even pictures assuming it to be of interest to others - the comings, goings and coming again of famous chefs at The Berkeley have been as fascinating as the peregrinations of the yellow warbler are to ornithologists.

Twelve years ago, Pierre Koffmann moved his three-Michelin starred restaurant La Tante Claire from its site at 68 Royal Hospital Road to The Berkeley, an early example of a top chef being lured to a top hotel. The Chelsea site vacated by La Tante Claire was taken on by the then relatively-unknown Gordon Ramsay, who three years later had three stars of his own. When Koffmann entered semi-retirement in 2003 (semi- in that he kept on a consultancy gig) and closed La Tante Claire, the by now very well-known Ramsay was taken on by The Berkeley's owners, Maybourne, to oversee all their restaurants. His two-starred, Marcus Wareing-helmed Pétrus replaced La Tante Claire, and Jean-Georges Vongerichten's fusion temple Vong was booted out to make way for Gordon's smart-casual Boxwood Cafe.

Fast forward to 2010, and following very public fallings out between Ramsay and Maybourne (which only Gordon Ramsay at Claridge's survived), and between Wareing and Ramsay, a practically unchanged Pétrus is now Marcus Wareing at The Berkeley and the Boxwood Cafe site - empty since April 2010 - has been taken on by...none other than an un-retired Pierre Koffmann. Plus ca change, as M. Koffmann might say. I tell you all this by way of bringing home the point - to non-ROD sufferers - that in London restaurant terms, Koffmann's is A Very Big Deal Indeed. It's for this reason that I chose to go there for Sunday lunch with my friend Nina, who on her occasional visits from Bermuda entrusts to me the choosing of somewhere fabulous for a long, boozy catch-up meal. To my great relief and pleasure, Nina's trust was repaid by Koffmann's being every bit as good as I had expected it to be.

In keeping with the reputation of The Berkeley itself, everything about the restaurant is discreetly luxurious, all pale surfaces and gentle lighting, with cheerful flashes of colour provided by green-upholstered chairs and some wonderful floral arrangements. It's smart rather than formal; Nina and I were in our Sunday best but other diners were in jeans and didn't look out of place. The size of the tiered room - there are two dining rooms separated by a very chic bar area on the landing between - would allow for more tables than there are; the resulting generous spacing adds to the air of relaxed elegance.

The Sunday lunch menu, offering three choices for each of three courses, is exceptional value at just £26, round about the price of a main course on the a la carte (the cuisine may be 'the simple, rustic...food of the countryside' but the prices are very much of the city). To kick off, Nina chose chicken liver parfait which was excellent, a hint of anise lifting it above the ordinary although its being served in a teeny-tiny Kilner jar seemed a little gastropub. My salad of hearts of palm with shrimps was much more in keeping with the surroundings; well-presented, colourful and classy. The crunchy shredded hearts were dressed in a lovely mustard/citrus emulsion full of flavour but not so much as to overwhelm the fat, sweet shrimps on top.

We both chose the same main course, braised shoulder of lamb with white bean cassoulet, and there could be no better example of the 'hearty, robust seasonal food' which it is Pierre Koffmann's stated intent to provide. The lamb was soft and rich, shaped into a neat cylinder and served on a bed of the hearty but not heavy stew. We were pleasantly surprised to be served a trio of complimentary side dishes (quite why they were complimentary I wasn't sure, but let's just say Nina is a very attractive woman) of honeyed carrots, green beans and  - a little oddly given our menu choices - French fries. All were good, although I thought the little metal pail the chips were served in was naff rather than nice.

We shared a flawless dessert of caramelised oeufs a la neige - more commonly known as ile flottante or floating island - a featherlight cloud of meringue atop a sweetened custard. Having spied, and smelled, the cheese trolley from across the room we shared a selection of the magnificently kept cheeses from La Fromagerie, two cow's and two goat's milk of which our favourites were the smooth, strong Fougeru and a salty Persille du Marais. A bottle of Corbieres Classique, Chateau Ollieux Romanis 2008 at £28 saw us through the meal, light enough to complement the starters yet robust enough to match well with the richness of the lamb and cheese dishes.

Service was generally as excellent as it should be in an establishment of this pedigree, but a couple of inadequacies stuck out. The waiter who took our food order would not take our wine order, but the sommelier sent to do so did no more than write down the name of the wine I had to point to on the list. The amuses-bouche we were presented with was no more than an anchovy fillet wrapped around a black olive on a disc of near-stale bread and the petits fours served with coffee, miniature chocolate macarons, were fridge-cold and chewy. These little freebies are lovely if they add something to the meal but if the desire isn't there to provide good ones, I'd rather have none at all.

These though really are minor gripes and don't in any way affect my opinion that this is a restaurant worth obsessing over. The food is superb, the atmosphere comforting and the service respectful but warm. It's not horrendously expensive either; our beautiful lunch, a good bottle of wine, a port, coffees and service came to £56 each.

The next time Pierre Koffmann retires it may be for good. ROD-sufferer or not, I'd recommend getting yourself to The Berkeley and catching him while you can.

Koffmann's, The Berkeley, Wilton Place, London SW1X 7RL Tel: 020 7235 1010 http://www.the-berkeley.co.uk/koffmanns.aspx