Bar Boulud, Knightsbridge

The excitement of Daniel Boulud opening a London outpost of his successful New York City restaurant Bar Boulud (beware of the horrific music) was evident when it was announced sometime last year. Twitter, as is the snowball nature of the medium, went into a frenzy. I only had one question on my lips: would Daniel be bringing his DB Bistro Moderne Burger with him to London? Well, the answer to that is yes he will, but for now he offers up three burgers on the London menu (once again, navigate to the bottom left to turn off the offensive music). The Yankee burger is a grilled beef patty with iceberg lettuce, tomato, sweet onion and pickle served in a sesame bun; the Piggie crucially includes BBQ pulled pork; the Frenchie goes gourmet and includes confit pork belly as well as other things that aren't suitable for a hamburger.

Marcus and I decided to go for the £20 lunch prix fixe, to get a bit of scope from the menu. The prix fixe fortunately included the Yankee burger and I had to try the hamburgers which have garnered a lot of praise recently, in the midst of a sort-of 'hamburger renaissance' (or even a naissance) in London. As Daniel himself once said: "I would like to think I may have been at the forefront of the burger renaissance". I assumed I would be in safe hands.

The prix-fixe menu. It seems to have changed slightly since the first week or two of opening. Three options for each course, three courses for £20. Seems a good way to go at lunchtime.

Soupe de pois. Chilled pea soup, toasted croutons, carrots and peas as part of a 'spring fricasse', rosemary cream, mint garnish. A generous portion of refreshing soup to match the season.

Enough about soup, I was here for the Yankee burger. Usually £12 (add £1 for cheddar cheese; no Kraft available, unsurprisingly...) it falls under the same price range as Goodman and is slightly cheaper than the burger at the Hawksmoor. Let's lift another quote once uttered by Daniel Boulud, on what makes a great hamburger: '1. Great bun, well toasted. 2. Great, juicy meat, well seasoned and cooked just right. 3. Fresh garnishes; the lettuce and tomato should be top quality.' In order: the bun here is great. It's utterly superb. One of the most aerated burger buns I've ever had the pleasure of holding/biting in to - air pockets for miles, a good structure and a taste that doesn't detract from or overshadow the burger. A good burger bun should be like Daniel's fellow countryman, Claude Makelele; you don't notice what it's doing, but it does the job well and keeps everything moving. That it is baked in-house is no surprise to me. In fact, most things here are made in-house, except the ketchup which I am informed they are "working on."

The second element that Mr. Boulud claims is needed for a great burger is the quality of the meat. Good quality, of course, but it also has to be juicy, well seasoned, cooked 'just right'. I ordered mine rare. It came out medium/medium-well. Marcus ordered his medium. It came out well done. I tried the old 'squeeze test'. It failed. In fact, it was so cottony and dry, I envisaged a fly or some dust coming out, like I was in a cartoon. I suspect they are using meat which is slightly too lean, but I also suspect that attention wasn't paid to the cooking (chargrilled) of our burgers; they were close to burned on the outside - which provided a needed crunch, albeit an unpleasant one - and cooked too much in the middle. These weren't cooked 'just right', I'm afraid, and it was a struggle to finish the burger in all honesty, despite there being evidence of good, Aberdeen Angus meat (from Smithfield). On the final element, Daniel claims that the garnishes must be top quality. The lettuce here was crunchy and fresh, but the tomato was, as is commonly the case, flabby and watery.

Some may ask why we didn't send the burgers back. I'll say this: if a kitchen so well drilled can't get a burger right the first time it is sent out, then that's what I'll judge it on. If I sent it back and the replacement was perfect, the first attempt would still play on my mind.

Unlike the disappointing burger, the frites were outstanding. Thin, hot and crispy, they were some of the best fries I've ever eaten.

Gateau chocolat-framboise. Chocolate cake with raspberries: a bittersweet, high quality chocolate mousse; raspberry jam; Sacher biscuit; a scoop of raspberry sorbet. Unbelievable dessert. Haute cuisine seems to be all about taking a flavour and elevating it to levels beyond its capacity - using an ingredient at the peak of its life and concentrating the flavours into a package that is extraordinary to eat. The raspberries here were incredible, complementing the bittersweet chocolate mousse in an age-old marriage of tastes. The gateau was a success, falling on the right side of sweet, with the Sacher biscuit providing an enjoyable crunch at the base. The raspberry gelato, a somewhat refreshing aspect. It even had some fancy-schmancy gold leaf on it, just to show you they mean business.

Fresh baked madeleines (£4). Freshly baked and once again, exhibiting some true skill from the kitchen. Soft, light and a joyous accompaniment to an excellent espresso (£2.50). A high note to end on.

The bill. Around £64 for the both of us, great value for the food on offer, despite a disappointing burger. The starters and the desserts were fantastic, and by all accounts the burger is usually good, so I suppose we were perhaps unlucky with a slip in concentration from the kitchen. I'll be back to try out the fabled DB Bistro Moderne Burger soon.