“I won’t be able to leave before 7.30pm,” says Doobie. “I’ve got to watch Buffy.” “Buffy?” I ask, incredulously. “Yes, Buffy,” he says, shocked that I am shocked. “The episodes no longer run independently, so it’s imperative that you watch them all.” It’s an odd thing for Doobie to say. He’s an antique bookseller, and usually prefers to while away the hours reading Rilke or playing real tennis. But I haven’t seen him for ages, so I let it pass.

When Doobie has had his fill of vampire-slaying, we set off for Morgan M, a recently opened neighbourhood place in London’s Islington that offers tasting menus of four or seven courses. In preparation, I have hardly eaten a thing all day, and by the time we get there, I am not only ready to chew my own hand off, but so weakened by hunger that I trip over the front step and lurch headlong through the door. “Table for four in the name of Stevens,” I bellow, wagging my finger at the maître d’ in the hope that I’ll simply look like a very busy person compelled to do things in a flurry.

The restaurant is nearly full — not bad for a Tuesday — and it feels as if the clientele is made up entirely of architects and theatre producers. I look at the menu. Morgan M, it turns out, is the name of the chef. A chef who thinks he’s a vicar. “Only when a guest is touched by the spirit of my dishes have I succeeded,” he says on the opening flap. Gosh, I think to myself, I wonder what happens to the spirit of a dish when it dies? I continue reading. On the first page, the names of the dishes run into one another like people rushing to the butcher’s for the last lamb chop. On the next, the layout is more like a mind map, those colourful drawings that detectives use to help solve tricky murders. There is a garden menu, an autumn menu and a four-course option, while other menus, like a crossword, go sideways and down.

At this point, a man not unlike a woodland shrew offers me some bread. I bite into the baguette and begin to jitter. I know we are in for something good. The bread is crunchy and fluffy. It tastes of Paris.

The manager, who has a beard like a hairy hockey stick and a beaded brow, comes over to take our order. I am fond of managers with beaded brows. All the blood, sweat and tears for their craft — it’s heart-warming. The entire table opts for the autumn menu, a seven-course extravaganza at £39 a head, with optional wines to accompany each course for an extra £19. I am so excited that I can feel the blood cells rushing around my head like crazy schoolchildren.

Soon enough, we’re off. The light cream of turnip soup with white truffle oil arrives in what looks like a cardinal’s hat. It is utterly delicious, the pungency of the truffles taking a supporting role rather than stealing the show. Nobody speaks until we’ve scraped it dry. Next, three of us have the ballottine of foie gras from the Landes — a rich and creamy, pink Barbara Cartland number, accompanied by a saucy grilled French quail. Tamsin offers me a bite of her seared diver-caught scallop, white chicory tarte tartin and onion soubise. I taste it and disappear into a celestial haze. “What are you doing?” Tamsin asks with horror. “You’re covering it in spittle.”

I start to panic that my stomach is filling too quickly. We’ve only had a couple of courses and my senses are already reeling. If I’m not careful, I will lose my thread completely and smash into some kind of wonderwall. I realise I am going to need serious resolve and strength if I’m going to make the distance.

The seared pavé of wild sea bass arrives, accompanied by a poêlée of crayfish, spinach and chive beurre blanc. The fish is cooked to perfection, the sauce wickedly creamy. The bits of crayfish nudge me closer to the edge. “Pink prizes of bliss,” I say, delirious. “Pink prizes of bliss.”

We are now at the point my husband calls “half time”. There is a break in proceedings. I am beginning to feel strange and fuggish. Stoned, even. I realise that I’m sitting next to the radiator; its warmth is zapping both my thigh and my strength.

I swap places with Tamsin. No sooner have I done so than the pot-roasted venison arrives, with ravioli of hare, glazed apple and chestnuts, and sauce grand veneur. The hare is too punchy for me, but the venison is tender and subtle. By the time we have licked our plates into oblivion, an extraordinary fatigue begins to do furious battle with my resolve.

All too soon, a brandy snap appears, filled with a light vanilla rice pudding and an unusual orange tuile. We consume without question. We are like sea-tossed penguins clinging desperately to the iceberg of our table.

“I’m not sure I can go on,” says my husband. “But the fondant,” says Tamsin weakly. “We’ll have to forget the fondant,” I say. “It’ll push us over.”

The chef approaches. “Morgan M,” we say, lacking the strength to look him in the eye. “We need the bill. No cheese, no coffees and certainly no fondants.” “But you haven’t had the best,” says Morgan M. “The best is to come.”

Four chocolate fondants appear, with Tahitian vanilla ice cream and an Armagnac drink. The fondant is one thing; the Armagnac drink, in a shot glass, with pistachio bits stuck to the rim like salt on a margarita, is something else. I want to lie in bed with it and stroke its brow and sing it lullabies. Doobie has his head thrown back, the glass jammed against his mouth. Tamsin is busy poking her finger into it. Marcus is furiously tapping it onto his tongue.

The bill arrives. With truffles. “This is too much,” we yelp, our heads capsizing onto the table. “We can’t handle it.” But one small, white chocolate truffle manages to make its way onto the back of my hand, and, as I lean in to suck it up, I realise I can. Beat that, Buffy, I think to myself, before passing out.

AA Gill is away

Truffle in paradise
Take the truffle
Trufflemaker
Truffle at mill
Truffle and strife

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