81 Fulham Road, Chelsea, London SW3 6RD (020 7581 5817). Meal for two, including wine and service: £180

The best restaurants have a special, unforced ingredient. At Bibendum, it’s the sunlight. On a clear spring day, the vaulting first floor space with its stained-glass window of the Michelin Man in shades of sapphire feels like a room where only good things happen. Grand restaurants are an encouragement to the grandiose, so let’s try some of that: without Bibendum, many of London’s great restaurants simply wouldn’t exist.

It’s justified. When Sir Terence Conran and Paul Hamlyn first opened it in 1987, with Simon Hopkinson in the kitchen, it showed the way. It was an unembarrassed celebration of a certain unforced luxury. Conran was a devotee of classic bourgeois French cooking, to a life basted in butter, and so was Hopkinson. He was armpits deep in the writings of Elizabeth David and Richard Olney. They loved steak au poivre and fish soup the colour of unpolished copper cooking pans. The bill was always huge, the wine list outrageous and the sense of self overwhelming. Great chefs like Jeremy Lee and Henry Harris, Bruce Poole and Phil Howard cut their teeth there. Without Bibendum, there would have been no Wolseley, no Quaglino’s, no Chez Bruce – or countless other London dining rooms.

But just because it mattered once doesn’t mean it has a right to exist now. It is a cruel truth that the very restaurant boom Bibendum helped ignite also made it redundant. The city has long boasted places in which to indulge similar bourgeois appetites and at less injurious prices. Hopkinson left the kitchen, but remained as both a partner and executive chef overseeing the menu. It did its particular thing, even as the city of which it was a part found new ways in which to feed us.

In 2015, they attempted a relaunch, but clearly it was not felt to be enough. This time they have gone the whole boned and boiled, pressed and spiced hog. Hopkinson has departed. In comes Claude Bosi, the cheerfully French bruiser of a chef who took his grand gastronomic enterprise, Hibiscus, from Ludlow to London and two Michelin stars. He has been given a shiny new kitchen and the dining room has been refreshed. On the face of it, this is a curious move. Bosi was never about classics. He was always about reinvention and “look at me”. He was always big on flavour, but also very big on clever.

At first there are fearful signs that he’s playing exactly this game: as a canapé, there is a faux black olive, with a crunchy shell and a liquid centre of tapenade, coating the mouth with caramelised onion and anchovy. There is an eggshell full of a coconut foam that tastes like your neighbour on the sun lounger smells, sprinkled with “curry powder”, an ingredient that only exists in fancy French restaurants. It’s all very clever, though unsettling.

But at the bottom of that eggshell is a simple, soothing mushroom duxelles – bold, serious and powerful. From that point onwards, everything settles. What emerges is Bibendum redux, a restaurant with a profound understanding of the simple virtues; of a classical repertoire which is robust enough to take a little refinement.

There are not enough veal brains on British menus. I mourned the passing of Racine when that closed, because they did them so well in a caper-studded beurre noisette. Here, a lobe is lightly breadcrumbed and then sautéed to golden. It wobbles as if still entertaining the odd thought, but there is crunch. It is served with a glossy take on sauce gribiche, the mayonnaise element replaced by a shiny veal jus, like the varnish of a dining table you can see your face in. It contains the finest dice of egg and cornichons. It is a dish using an ingredient others would reject, raised to a certain majesty.

In the same rescued, washed and scrubbed vein there is “My mum’s tripe and cuttlefish gratin”, an intense and serious stew of the two ingredients, each lending the other a leg up with funk and an encouraging stench. It is peppery and sticky. It comes with two thick, crisped slices of what Bosi calls a pig ear and ham cake. It is somewhere between a bakery item and a terrine. I want a loaf of it. The gratin reminds me of a fiery tripe stew that Simon Hopkinson still cooks; conscious or not it feels like a respectful nod.

The starters list is full of frog’s legs and sweetbreads and asparagus. A pretty crab dish brings a whipped layer of brown crab meat, topped by finely picked white crab, then a layer of gently understated elderflower jelly. What makes it sing is the temperature: just warm enough to allow the flavours their voice. Main courses include turbot and Dover sole, suckling pig and long-cooked goat. The latter is a take on surf and turf, the puck of sweet braised meat tumbling into its razor clams and a sauce made with sea vegetables. On the side is a bowl of Jersey Royals so tiny, they’re practically foetal.

It is all clean, focussed and viciously expensive. There is a lunch menu for £36.50, including a main course roast carved tableside. But otherwise starters run from £15 for the brains to £38 for a duck jelly with caviar. Mains are £24 for the tripe, up to £39 each for a chicken to share. Oh, huff and puff all you like. This is Bibendum staying true to itself. It is a room for “happy birthday” and “congratulations” and lips mouthing softly, “I love you”. It is one I’ll recommend when emails arrive, announcing milestones that need a restaurant by which to mark them.

Of course, the wine list is gruelling; it’s a tortuous Russian novel with too many characters. But there’s an interesting choice by the glass which begins at £5.50 for a totally acceptable sauvignon blanc.

We finish with a wild strawberry “vacherin” looking like something from a fancy jewellers. There is a ball of spiky meringue enclosing creams and coulis and fruit. I didn’t know whether to wear it or eat it. This is a lie; I knew exactly what to do with it.

Finally, there is a pneumatic chocolate soufflé, its surface sauced and shiny, and imprinted with the outline of the Michelin Man. He is stabbed through the chest to allow for the insertion of a basil ice cream. The soufflé sighs as the quenelle slips in and so do we, for everything here is quite as it should be. Welcome back, Bibendum, I’ve missed you.

Jay’s news bites

■ I have previously referenced Quo Vadis, where Bibendum alumnus Jeremy Lee is chef, but since the whole place has had a shake-up, to make space for Barrafina, it’s worth noting again. God, it’s good. From his smoked eel and horseradish sandwich to pies under a suet-rich pastry shell through to the likes of buttermilk pudding with lemon curd, it has that rare thing: a menu that is an expression of the good taste of the man in charge (quovadissoho.co.uk).

■ Neil Rankin is to open a second branch of his open-fire meat restaurant, Temper, this time in London’s Angel. The plan, Rankin says, is for each one to have a slightly different flavour profile. At the Soho original, reviewed here recently, it’s tacos and Mexico; the Angel branch will look to the Indian subcontinent.

■ Crowdfunding news of the week: renowned Brighton Indian restaurant the Chilli Pickle is campaigning to raise funds for a roll-out across the south of England. They are looking at towns like Winchester and Tunbridge Wells. For more information, visit growthdeck.com

Email Jay at jay.rayner@observer.co.uk or follow him on Twitter @jayrayner1