"What can sex 18 hanwe do to help?" That's the question Ryan Riley asked himself when people began experiencing loss of taste and smell as a result of COVID-19.

As the founder of Life Kitchen, the UK's first cancer cookery school, Riley has a background in adapting recipes for people experiencing taste and smell loss from cancer. Certain cancers and some forms of cancer treatment can bring about changes to taste, smell, and oral sensations. "With Life Kitchen, we've always focused on helping people with cancer, but when COVID happened, we had people coming to us saying, 'Can you help? Can you do anything?'" Riley tells me.

That help now comes in the form of Taste and Flavour, a free book with 18 recipes for people experiencing taste and smell changes as a result of long COVID (symptoms that last after the infection has gone). You can download a free digital copy of the book online. It's split into three sections — Snacks, Substantial, and Sweets — and features recipes like preserved lemon, feta and Za'atar twists; mushroom, apple, and ginger ice lollies with Shichimi Togarashi dip; blue cheese mac 'n' cheese (see below for recipe); and sambal butter noodles (see below for the recipe).

"We spent years working on taste and smell loss for cancer so everyone kind of assumed, naturally, we'd be the right people for this. And so did I in many ways, but actually, it's been a completely different process to what we thought it would be," says Riley. When Life Kitchen co-founder Kimberly Duke and Riley set to work, they discovered that COVID taste and smell loss has key differences to what they usually work with.

"With COVID, there's three different groups that people fit into," explains Riley. "There's people who just lose their sense of taste for the first two weeks that they have it, there's the people who lose their sense of taste or sense of smell, which is anosmia. And then there's parosmia which is a distorted sense of smell."

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"Quite a lot of people who have COVID find garlic, onions, eggs, roasted meats really repulsive and that's because they've got a distorted sense of smell," says Riley. They've had to develop recipes that don't include those ingredients.

But in removing those trigger foods like garlic and onion from recipes, another issue comes up: how do you build flavour? "I've been a cookery writer now for four years, we're told to build a recipe's flavour with garlic and onion, we've had to flip of the idea of cookery, and what we know about recipe writing on its head," says Riley. "So, we've eliminated all of those trigger foods from the recipes to make them what is known as 'safe food' and then we've added all of the principles that we use in Life Kitchen to try and elevate those safe foods to be absolutely delicious."

For the book, Riley and Duke worked with Professor Barry Smith — the UK lead for the group researching loss of smell as a COVID-19 symptom — who produced the first research paper on the effects of COVID on taste loss. Riley got COVID last March but tells me he had every other symptom except loss of sense of taste and smell. As part of the recipe development process it was vital that people who've experienced this symptom were able to test the recipes and provide honest feedback. "To write the book, we rounded up a group of between 10 and 20 people with long COVID and we sent them the recipes, and we got them to try it," says Riley, who says Life Kitchen's projects have always been based in science and involved testing — and as COVID itself evolves, so does the science. "We sort of had to go down the middle and take on board people's critiques and reviews while trying to ensure that we stick to a level of science that we knew and understood and can back up," says Riley. They ended up testing around 150 to 200 recipes in the development phase, and whittled it down to 18 recipes for the book.

The feedback they got from people with long COVID proved indispensable. One of the mistakes they made was not looking at the added ingredients on a sauce, Riley tells me. "As I mentioned, garlic and onions are trigger ingredients. But it's not often that you look at added ingredients and what's in them," says Riley. One of the recipes in the book is for sriracha beans. "Sriracha sauce has garlic and onions as the base," says Riley. Recipe testers pointed out the error that had been made, and they've since substituted the sriracha for Tabasco, which is high in vinegar and good at stimulating the palette according to Riley.

Related Video: I was born without the ability to smell. Here's what you need to know about COVID smell loss

At Life Kitchen, Riley uses five elements: aroma, umami, texture, layering, and trigeminal food sensations (the tingling, burning, and cooling feeling you get from spices). They used these five basic tastes when creating recipes for Taste and Flavour.

"Umami is what we see as the most important," says Riley. "Your umami is the savoriness you get in soy sauce, cheese, mushrooms, and miso. So we've looked at adding all of those different umami rich flavors in the recipes, to add that deep, rich, savory comfort."

Following COVID, food may taste "bland, salty, sweet, or metallic," according to the National Health Service. The NHS recommends adding adding spices, herbs, and sauces to food to improve flavour. Riley says spice and heat will always help, but it's that umami that's key. "Bringing in that deep rich savoriness when you have umami-rich ingredients, they stimulate all of the all of taste buds and your palate," says Riley. "So I would always say try and get as much of umami into your food, try to add a tablespoon of miso, a tablespoon of soy sauce, grate some parmesan over that pasta, try to really push the flavours as high and as powerfully as you can."

5,000 copies of the physical cookbook are available to be ordered on Riley's website, with just the £3.00 postage fee to be paid. Once those copies are gone, the book will be available to download for free as an ebook from the website. At the time of publishing there were 378 copies left in stock. Non-UK residents can download a digital copy of the book on the website.

Now, if you want to try a few out...

Mushroom and blue cheese mac 'n' cheese

Serve sprinkled with the breadcrumbs for texture. Credit: CRAIG ROBERTSON

Serves four

Ingredients:

400g (7oz) dried pasta of choice (we used chifferi rigati)

2 tablespoons vegetable oil

100g (31/2oz) shiitake mushrooms, sliced

1⁄2 teaspoon cracked black pepper

zest and juice of 1 lemon

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470g (1lb 1oz) jar of béchamel (white) sauce

90g (31/4oz) blue cheese of choice, crumbled

100g (31/2oz) parmesan, finely

grated, to serve (optional)

For the breadcrumbs:

2 slices of your choice of bread

A large handful of basil leaves picked

Directions:

Preheat the oven to 200°C/180°C fan/400°F/Gas 6.

First, make the breadcrumbs. Place the bread and the basil leaves in a food processor and blitz to fine crumbs. Tip the crumbs on to a baking tray and bake in the centre of the oven for 10 minutes, until golden.

Meanwhile, bring a large saucepan of salted water to the boil and add the pasta. Boil according to the packet instructions until al dente.

Reserve a cupful of the cooking water.

While the pasta is cooking, heat the oil in a large frying pan over a high heat. When hot, add the mushrooms and pepper and fry for five to six minutes, until the mushrooms are golden brown. Add the lemon zest and juice and cook for a further one minute to allow the mushrooms to absorb some of the juice. Add the béchamel sauce and cheese, then stir occasionally, until the cheese has melted.

Drain the cooked pasta and tip it into the pan with the sauce. Stir well, cook for two to three minutes, until the sauce has thickened around the pasta (add some reserved pasta water, if it’s looking dry), then serve sprinkled with the breadcrumbs for texture, and a little parmesan, if you wish.

Sambal butter noodles

Toss these noodles vigorously. Credit: CRAIG ROBERTSON

Serves two

Ingredients:

75g (21/2oz) unsalted butter

2 teaspoons sambal oelek (we like the brand Lucullus) or chilli paste

a large handful of basil, leaves and stems roughly torn, plus optional extra leaves to serve

260g (91/4oz) dried egg or rice noodles

150g (51/2oz) parmesan, finely grated

1 lemon, halved

Freshly ground black pepper

Directions:

Melt the butter in a large frying pan over a high heat until foaming.

Whisk in the sambal paste and add the torn basil leaves.

Bring a large saucepan of salted water to the boil. Add the noodles and cook according to the packet instructions, until tender.

Meanwhile, add a ladleful of the noodle water to the pan with the sambal butter, and allow to bubble away to reduce for 10 seconds or so. Add half the parmesan and stir to combine. Once the parmesan has melted, add another ladleful of noodle water and the remaining parmesan, stirring until the cheese has melted and the sauce is the consistency of double cream. Season with black pepper.

Drain the cooked noodles and add them to the pan with the sauce, tossing vigorously to coat.

Divide the noodles between 2 serving plates. Spritz with the lemon halves, and sprinkle over a few more basil leaves, if you like.