The Dock Kitchen, Portobello Dock, 342/433 Ladbroke Grove, London, W10

Dock Kitchen is a pop-up restaurant that never popped back down. Housed in the HQ of furniture maestro Tom Dixon – and with a chef whose talents are matched only by his tousle-haired looks – it was destined to bring some razzle-dazzle to the dusty northern-most border of Portobello. It opened last September as a supper club (themed menus, no choice) to rapturous reviews, but flavour of the month can quickly become stale left-overs, so I waited till the fuss died down to visit.

On a balmy Saturday night I arrive at an unprepossessing metal gate which one buzzes to enter. Inside, a canal cul de sac gives the courtyard and first-floor dining space a faintly rural look and, once the gate clangs shut, it's just possible to forget the Sainsbury's across the road and thundering lorries on the nearby Westway.

Tonight's cuisine is southern Italian (chef Stevie Parle, late of the River Café and Petersham Nurseries Café, is well travelled: other supper themes have been Scandinavian, Lebanese and Sri Lankan). He's toiling away in the tiny galley kitchen as the rest of the long dining-room, all glass to one side and crammed with ultra-chic furniture, quickly fills up.

I'm going to make this quick, and you'll see why. It wasn't great. The four-course menu came out painfully slowly, and as we were the last to be served every time, each dish was cold. It didn't matter too much – even the octopus, clams, scallops and mussels medley tasted good lukewarm – but it was a bit dispiriting at £35 a head (without drinks). Our tenerume soup was cool and a little less generous than our neighbours', while the main course of seabass cooked in crazy water (which sounds better in the native Italian, acqua pazza) was all bones and bits. A cherry granita was delicious, but served in small glasses with big spoons, so much of it stayed in the bottom, unreachable.

But still. There was real skill in the cooking and when I discovered the dining space had just been reconfigured to add many more tables, I felt Dock Kitchen might deserve a second chance. So, on an even more balmy Wednesday lunchtime, I pedal across London to eat the daily changing lunch menu. Arriving hot and cross, I sit radiating heat while a young waiter brings me home-made lemonade, which slakes the thirst beautifully. Things are looking up as I peruse the menu.

Four starters, four mains, four puds – and I want to eat them all. I go for three toasts, one each of spicy Calabrian sausage, fresh ricotta, and smashed broad beans (very tricolore, £7.50); Mr M chooses bull's heart tomatoes with sumac, za'atar, lemon and herbs (£6.50), because he figures to charge that for a plate of toms, they must be good. And they are – soft texture, er, bullish flavour, and scattered with pretty little edible flowers. I'd have happily eaten nine toasts, 12 even. They are simple ingredients at their peak, allowed to shine.

Griddled salt-marsh lamb chops with smoked green wheat, aubergine and tahini (£14) packs a punch, the aubergine soft and cinnamon dusted, the lamb tender and juicy. The wheat, which Parle later tells me is known as frikkeh in Middle Eastern shops, is frikking good (sorry, can't resist). Soft, nutty and far, far more interesting than cous cous. Meanwhile, Cornish yellow chicken in milk, sage, lemon peel and white wine, with courgettes (£14) is a thing of subtlety and, after the toast starter, it's a pleasure not to have a plate loaded with more carbs. We sit on our hands to stop from picking up the meaty bones and gnawing them.

A pause while the young waiter briefly forgets us gives me the chance to peruse the other diners. It's archetypal architect-types – fiftysomething women in expensive tunics and flat sandals, men in shades of grey with BlackBerry/iPhone sandwiches at their elbows. If I worked round here and had the lunch budget, I'd be a regular too.

A Lebanese pistachio ice-cream and a white peach crostata (£5 each) are utterly delicious – the ice-cream having an almost chewy texture and the peaches juicy and just the right side of tart in their tart. And I needed the fuel to cycle home.

Once front of house is up to speed, Dock Kitchen will be unmissable. I intend to go back before Stevie Parle pops up in some swanky West End address.

12/20 & 16/20

Scores: 1-9 stay home and cook, 10-11 needs help, 12 ok, 13 pleasant enough, 14 good, 15 very good, 16 capable of greatness, 17 special, can't wait to go back, 18 highly honourable, 19 unique and memorable, 20 as good as it gets

The Dock Kitchen Portobello Dock, 342/433 Ladbroke Grove, London W10, tel: 020 8962 1610 Lunch and dinner Tuesday to Saturday. £26 a head for lunch, £35 for dinner, not including drinks

More insider info

The River Café

Thames Wharf, Rainville Road, London W6, tel: 020 7386 4200

This world-famous Italian which started off as a works canteen has reopened (after a refurbishment forced by a fire) with divine food, though its eye-popping prices are still high for such simple fare

RIBA 66 Portland Place, London W1, tel: 020 7631 0467 A pretty, tucked-away garden and impressive Art Deco interior are the main draws to the café of this 1930s-built institution; food is incidental

Sotheby's Café

34 New Bond Street, London W1, tel: 020 7293 5077

Tucked in to the auction house – off the foyer, in fact – this small but very classy café offers a perfect perch for a people-watching lunch; food is surprisingly good value, too

Reviews extracted from 'Harden's London and UK Restaurant Guides 2010'. www.hardens.com