Duck & Waffle, 40th Floor, Heron Tower, 110 Bishopsgate, London EC2

Can the food match the views at the vertigo-inducing Duck & Waffle?

It's never great to arrive at a restaurant ashen-faced and shaking, but for those with a fear of heights, it's a distinct possibility at Duck & Waffle. Forty floors up London's glittering Heron Tower, the place has jaw-dropping views and a delightful atmosphere; it's just that the vertigo sufferer will need a few minutes and a stiff drink to recover from the high-speed journey up in a glass lift.

Luckily a stiff drink at D&W comes in the form of a special yuzu-accented gin and tonic, which does much to put me in the right mood. My more robust friends Russell and Kornelia have glasses of English fizz of the moment Nyetimber (it seems only right, since they're still in the afterglow of their honeymoon).

As they prowl around the floor-to-ceiling wraparound windows, noting everything from Wembley Stadium to the Olympic Park, I feel safer staring down at the menu. Why am I putting myself through the ordeal of a vertigo-inducing venue? Well, Duck & Waffle has been the talk of the foodie town since it opened a fortnight ago; for its location, its rather bonkers eponymous signature dish and for its 24/7 opening hours.

I'm here for dinner as the sun sets. The bar, through which you walk from lift to dining-room, is heaving with City folk, most of whom have their backs to the window. I guess they work if not in this skyscraper, then one of its neighbours, so they don't need to rubber-neck like us.

The room has long, hefty, wooden tables for large groups, and semi-circular banquettes with marble tables for the likes of us. The staff are in blue button-down shirts and appear to have – at this early stage – enough pep to cope with the 3am club kids in search of posh burgers and the 5am power-brokers refuelling on a foie gras all-day breakfast.

Yes, that's a thing here. Like the duck and waffle (£12, two classic waffles stacked with a big old confit duck leg and a fried duck egg and a jug of mustard maple syrup), D&W goes the extra mile in high-energy, wham-bam flavour combos. That foie gras on brioche (£10) is topped with bacon, a dinky egg and a thick slick of chocolate spread. Roasted beetroot with goat curd (£7) has great shards of honeycomb (the Crunchie kind, not the bee kind) over it. I find it a bit much, but those with a sweet tooth are in for a treat.

Mind you, chef Daniel Doherty, the cheerful tattooed blur in the open kitchen, obviously gets off on tang, too. Crispy pigs' ears at £4 (served in a paper bag) have a hefty barbecue seasoning that requires quite a lot of a deliciously crisp El Muro Macabeo Spanish white wine (£25) to slake. Another of the "small plates" is Dorset scallop with apple and lime (£7). The plate is no such thing. What looks like a block of pink marble turns out to be salt, for infusing the dinky cubes; the delicate mollusc almost gets swept away in overpowering salt and citrus. Nice crunch, though.

Our ordering has been as ecletic as the menu. Between three, we're not sure how many snacks, small plates, brick-oven dishes and "for the table" offerings to assemble. Our waiter says the idea is to order what you fancy, and they can bring more quickly if you're not full. This suck-it-and-see approach makes me a little uneasy but it turns out that with a small dish of an unctuous burrata with capers and pickled red onion (£8), spiced lamb cutlets with smoked aubergine purée (£12) and octopus with chorizo and lemon (£9) from the wood oven, we're sated. We certainly didn't need the extra cutlets the keen-eyed and ultra-efficient manager Gavin brought over as a "sorry" for a dodgy flatbread, but we managed to put away the tender, smoky little buggers anyway.

I can't manage more than a teaspoon of our shared, sublime torrejas with maple-caramel apples – the Spanish-y French toast is so rich and creamy and the apple so toothsome, I fear that if the plunge down in the lift doesn't get me, the sudden onset of diabetes might.

The food at Duck & Waffle is not faultless, but the experience is; and there are plenty of enticing dishes I didn't try (a whole roasted chicken beckons). On the way out, I ask the chef if he's ready for the travails of the all-nighter. He says he can't wait, and promises night owls the chance to challenge him to concoct something using the kitchen's "toys". It sounds fun. I can't wait to go back.

8/10

SCORES: 1-3 STAY AT HOME AND COOK,  4 NEEDS HELP, 5 DOES THE JOB, 6 FLASHES OF PROMISE, 7 GOOD, 8 CAN'T WAIT TO GO BACK, 9-10 AS GOOD AS IT GETS

Duck & Waffle 40th Floor, Heron Tower, 110 Bishopsgate, London EC2, tel: 020 3640 7310 Open 24 hours a day, 7 days a week; £120 for two, with wine

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Reviews extracted from ‘Harden’s London and UK Restaurant Guides 2012 www.hardens.com