Khao So-i, W1

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Here’s the thing: if you’re only going to offer one dish at your restaurant, you have to be really, really good at it. If you’re not, you’re going to have a problem.

Khao So-i has a problem.

To caveat that, before last week I’d never eaten khao soi, the northern Thai noodle soup that gives Khao So-i its name. I went along with a friend who has, often though long ago during a backpacking jaunt through south-east Asia, but I’ll make no pretence that I can tell you whether this version is authentic, or accurate, or anything else of the sort.

And if you want another caveat, Khao So-i does have other options on its menu, though only its starters and desserts — there are no other mains at all. Which is a particular shame, because everything else we tried, right down to the cocktails and craft beer, put the titular noodle soup to shame.

Founded in Chiang Mai four years ago, Khao So-i now has a few sites in Thailand, but the new Fitzrovia restaurant is its first abroad, following a brief pop-up in the area last year. The dining room is dimly lit and modern, all sharp lines and wood panels, a hip hop soundtrack thrumming along in the background. It’s loud, buzzy, and cramped, fun for a quick dinner but not somewhere you’ll want to linger too long.

The tone is appropriate enough, given that husband-and-wife co-owners Win Srinavakool and Por Haruethai Noicharoen describe this as a modernised take on a traditional dish. They’ve made it creamier and saucier, cut back on the oil, switched up the noodles, and present it, along with its various toppings, on a tray so that you can tweak your bowl as you go. That’s probably context that makes more sense in its Chiang Mai and Bangkok branches, but is unlikely to come across clearly to diners in London, where khao soi is rarely found on Thai menus. We’re getting the deconstruction before we ever got the original dish.

None of which would matter if it wowed, of course. We order the soup two ways, one topped with chicken and one with thin slices of both braised beef shank and torched chuck eye. Both yield disappointingly small bowls for the asking price — £19.50 for the chicken, and £24 for the beef, though you can climb all the way to £49 for a langoustine version if your pockets are feeling uncomfortably heavy. There’s plenty of protein, to be fair, with generous folds of beef and a whole chicken thigh, each the best parts of their respective bowls, but the meagre portions of noodles and broth rather rob this of the warm embrace that the best bowls of soup provide.

The noodles themselves arrive soft, a little over-cooked, though the textural contrast with the crunch of deep-fried noodle shards helps. The broth has a welcome sour edge, but that’s about the only flavour able to cut through the rich, creamy coconut base. The final effect is curiously mild — no matter how much lime, chilli, or pickles I added into the mix, it remained somewhat thin and unsatisfying. Taken together, this isn’t a bad bowl of noodles, but it’s not an especially good one either.

It does help that the rest of the menu is much better. Moo ping, skewered slabs of pork belly destined to be dipped into marinated egg yolk, are the clear standout, the rich, fatty pork and creamy yolk creating a meltingly tender combination. A blackened chicken thigh, served alongside sticky rice, is less novel but has been grilled with just as much craft and care, and the sharply spiced dipping sauce gives a welcome acidic kick. These small plates are worth pairing with something from the short cocktail menu, dominated by Thai twists on classic drinks, like a lychee-based French 75 or a Bloody Mary bolstered by curry paste and tamarind. Beer comes from Neckstamper Brewing — a new one to me, though its fruity, hop-heavy table beer proves a perfect pairing.

Khao So-i has already earned a bit of a reputation for its tea cheesecake, a new invention for the London branch. It’s not much of a looker, baked to a murky shade of greyish brown, but the texture is perfect: dense but soft, with none of the undercooked gooiness that’s taken Instagram cheesecakes by storm. The tea lends a savoury bitterness that keeps the cake from ever feeling cloying, and provides the all-important excuse to pour over every drop of the coconut cream provided on the side.

Almost everything I ate or drank at Khao So-i was great, but when the only dud is also the star attraction, “almost” doesn’t really cut it. I’d tell you to just go and order something else, but that isn’t really an option unless you’re willing to dine on nothing but small plates and cheesecake, which I wouldn’t rule out, but does feel like it’s slightly missing the point. So no, I suspect I won’t be back for more from Khao So-i, but I will be on a mission to track down khao soi elsewhere, to figure out what they were trying to reinvent in the first place.