Whitechapel Gallery Dining Room, 77-82 Whitechapel High Street, London, E1

The gentrification of east London gallops onward. You can hardly move in Shoreditch or Hackney these days without encountering a new private club or school-of-Mark-Hix restaurant. Whitechapel, long a place of anonymity, grot and serial murder, is on the turn as well. Through the windows of the Whitechapel Gallery's spanking new Dining Room – launched just after the Gallery's re-opening, following a two-year, £13.5m renovation that doubled its size – you look gloomily at the disused buildings across the High Street. But inside the Dining Room, everything is pure Primrose Hill, clean and new, tasteful and sweet-smelling.

It's hellishly small, though: neighbouring lunchers, when exiting their table, have to inch past you sideways so as not to get their jacket-hems in your steamed greens with lemon oil and toasted almonds. It's a cute room, light and airy, whose long vertical mirrors create an illusion of spatial adequacy and the blond-wood floor, wooden tables and wood-and-leather chairs howl "Scandanavian chic".

Remarkably for a gallery restaurant, there's no art on the walls. As we discovered, they keep it for the dishes. The menu is as small as the room (four starters and four mains) and features lots of seasonal, hedgerow-foraging stuff: dandelion leaves, wild garlic, herbs – hardly surprising, when the head chef is Maria Elia, late of the Delfina Gallery in Bermondsey, and the author of The Modern Vegetarian. I liked the promise of "locally smoked eel" – I didn't realise there was a proper smokery in the backstreets of Whitechapel. It seems a far cry from the days when the only eels you'd get round here came with pie, mash and liquor.

We ordered hock of ham and Jersey Royal terrine with English asparagus. It arrived artfully arrayed in a long rectangular plate, a soft quail's egg adding a dab of colour to the green-and-white palette until suddenly we were looking at a Joan Miro painting. My date complained that the asparagus, though perfectly cooked, was oversalted, as was the hock terrine, while a spoonful of anonymous relish put her in mind of Heinz Sandwich Spread. My palate is less sensitive to salt, and it seemed fine to me. The wild garlic, leek and potato soup with Dorset Blue Vinney and crispy leeks was a livid shade of green, with the cheese parked on a floating wedge of toast. Visually, it was a Howard Hodgkin. Texturally, it was the consistency of mayonnaise, but it tasted fine. I usually dread this kind of car-crash cuisine, in which a vichyssoise meets a Welsh rarebit in a British-French pile-up; but all the flavours were intact and pungent, especially the garlic and the blue cheese.

The chef's veggie credentials were most on show in a signature dish called "textures of heritage carrots", in which the humble carrot is cooked four ways, in soup, pancake, hummus and herb salad, with a dill and feta baklava. (Isn't that a Greek pudding with honey and nuts?) I gave it a miss – who wants one gussied-up carrot dish, let alone four? – in favour of roasted rabbit, caper, rosemary and sage stuffing, with white bean purée and roasted fennel. It was a dark and murkily serious dish, all dirty browns and slightly over-roasted stuffing – like a Goya painting of death and mayhem in wartime. It was nice to be given, for once, a proper tranche of rabbit, rather than the usual selection of white bunny bits, although the capers rather overwhelmed the meat. The fennel had been roasted until the outer leaves were dry as papyrus, but it was fabulously tasty. The "smashed spuds", as the menu calls them, reeked nicely of (unmentioned) tarragon in the crème fraiche. If you weren't a huge fan of tarragon or capers, this dish would have been a trial. Since I like both, I loved it. My date's pan-fried bream with brandade, charred baby leeks and golden beets was perfectly cooked and danced gracefully with the fishy mash below; even the golden beets (which I loathe) worked well with their partners. As with the fennel, enthusiastic charring brought out the best in the leeks. Ms Elia's devotion to capturing flavours, even of humble root vegetables, does her credit.

A closing treacle tart was insufficiently warm or gooey, or indeed, terribly treacly. But the rose-scented macaroon, with roasted rhubarb and white chocolate parfait, was a thing of loveliness: a Raoul Dufy landscape, in which twin piles of poached rhubarb were sailboats circling the ocean liner of white chocolate in its macaroon hull, and traces of rose liqueur rode like a gorgeous oil slick upon the waves.

The Gallery Dining Room is absurdly small, but it's got a big heart for both flavour and invention. I recommend you go quickly, while they're offering a two-course set lunch for only £15. Oh, and there's some art nearby, at which you might like to have a butcher's 'ook.

Whitechapel Gallery Dining Room, 77-82 Whitechapel High Street, London, E1 (020-7522 7888)

Food 4 stars
Ambience 2 stars
Service 4 stars

About £80 for two, with wine

Tipping policy: "Service charge is 12.5 per cent discretionary. It is distributed among the staff; all tips go to the staff"