(Bloomberg) -- Mexican food in the UK is famously bad, similar to other places around the world that don’t have many transplanted chefs from Mexico. You wouldn’t think ignoring the ingredients that define the cuisine would fix things.

But at London’s best Mexican restaurant, Kol, you won’t find staples such as avocados, tomatillos, mangos, cactus, coconut, and jicama. The most notable ingredient not in evidence at the Michelin-starred restaurant in the West End, where the tasting menu goes for £125 ($148)? Limes.

“In Mexico, you get a delivery of limes every day, a mountain of limes. You don’t have a Mexican restaurant without limes,” says Santiago Lastra, Kol’s chef and owner, who was born in Mexico City and worked in kitchens there.

But Lastra offers terrific foundational Mexican dishes—tacos, tamales, mole, and aguachile, the ceviche-style seafood dish that depends on the citrus for flavor—without limes. Not because he can’t get them in London, of course, but because his goal at Kol is to showcase the brilliance of Mexican cuisine through native instead of imported produce.

The chef does it by creating incredible hacks of ingredients that aren’t found in the UK, with just a few exceptions. He imports a handful of ingredients—specifically corn, chiles, chocolate, and coffee (“and mezcal,” he laughs) for which he can’t find adequate alternatives. As an added benefit, many of the products he sources support small, indigenous communities.

The chef, who worked as project manager for the Noma Mexico residency in Tulum in 2017, has cooked around the world, from Denmark to France to Taiwan. Everywhere he’s worked, he says, people have asked him to make Mexican food. He refused because he wouldn’t be able to source the quality of ingredients he needed.

Then he decided to think about cooking in terms of flavors, rather than components. Before he opened Kol in 2020, Lastra spent seven months in a test kitchen with his brother Eduardo, an industrial engineer, and a few chefs, perfecting alternatives to products that wouldn’t be as good when flown in. There are few things as disappointing as an unripe, untasty avocado.

Kol’s version of lime juice is made from fermented gooseberries, with a splash of aged black-tea kombucha. He’ll also use seabuckthorn, the fruit that grows wild on beaches around the UK. The result has the bright tartness of lime, rather than the flat-out acidity of a straight vinegar substitute. A tiny bowl of his lime juice accompanies just-cooked langoustine tacos with pickled onions; the shellfish head sits in the bowl, to be used as a mop for sprinkling the taco with the tart liquid.

His most brilliant innovation might be his “avocado,” made from pistachios and served pureed as a garnish on such dishes as crab and mushroom chalupas. “If you had a magic wand and could convert an avocado, it would become a pistachio,” says Lastra of the sweet, nutty taste they share. He purees the nuts with water to make a smooth, guacamole-like condiment that also includes roasted garlic, his fermented gooseberries/lime juice concoction, and a little chilis. The approximation to a very good avocado puree is uncanny.

Lastra insists that he’s not doing this to be gimmicky; he wants to highlight the potential of local products. At the same time, his goal isn’t to go to extreme lengths to recreate, say, a pineapple: “It’s not like Frankenstein.” The question, he says, is how to recreate something simple, like fruit. Take mangoes. “You start with: What is yellow?” Lastra says. “Butternut squash doesn’t taste like mango or have the same texture. But it’s yellow.” Next, he experiments with different treatments of squash, for texture and taste. For what became his mango puree, Lastra settled on a mix of raw, cooked, and pickled butternut squash, pureed with a little elderflower syrup to get the fruit’s floral hits and aged kombucha to blunt the vegetable flavor. At Kol, you can taste it as a pre-dessert sorbet.

Sometimes, Lastra’s hacked ingredient is pure serendipity. That’s what happened with coconut, which, improbably, he fashions from squid. (Yes, squid.) On a beach in Mexico, Lastra started snacking on a coconut he had left out in the sun. “I thought it was squid. It was warm coconut with the smell of the sea. And I said, ‘Oh my god, it’s like a perfectly cooked squid.’” At the restaurant, he reverse-engineers the dish, serving faux coconut as a dessert. (This wasn’t on the menu when I ate at Kol; as good as his inventive substitutions are, I fear that a squid that becomes a coconut is pushing it.) 

If an enterprising farmer grew avocados in the UK, would Lastra use them? “I’d have to try them,” he says, after a pause. “Not because I have to stick to my concept.” But, he says, “it would have to taste like an avocado I want to have.”

(Adds chef’s philosophy in fourth paragraph.)

©2022 Bloomberg L.P.