If a burger has no meat in it, can it still be called a burger? What about a plant-based sausage – is that still a sausage?

Henry Firth and Ian Theasby, the brains behind vegan phenomenon Bosh! certainly think so – and they’ve had the argument with Piers Morgan to prove it.

“He was trying to argue that a veggie burger shouldn’t be allowed to be called a burger, it should be called a ‘disc’,” remembers Firth of their 2019 appearance on Good Morning Britain.

“And a sausage shouldn’t be allowed to be called a sausage unless it’s made of meat – it should be called a ‘tube’, which is obviously a bit silly. Realistically, a burger can be made of plant-based ingredients now, or it can be made of animal meat. The same is true of a sausage, the same is true of bacon.”

With 844k followers on Instagram and 230k subscribers on YouTube, the duo bring vegan food to the masses and wrote their first cookbook in 2018. Each book since then has tackled what they see as a ‘problem’ – whether that’s misconceptions around vegan food as being expensive, or that it’s time-consuming to make.

For their latest book, the London-based vegans, both 39, are looking at the thorny issue of texture.

“One thing that happens when you first adopt a plant-based diet is that it can be quite difficult to find good bite, good chew and good mouthfeel – exactly the sort of textures that meat gives you,” explains Theasby.

“And we wanted to show you that you can get those meaty textures, those meaty flavours from plants – as well as animals.”

Theasby and Firth have both been vegan for over eight years, and things have changed drastically in that time. Many of the recipes in the new book feature meat substitutes, such as plant-based ‘chorizo’ or ‘chicken’, which, while common now, is a relatively new phenomenon.

“When we first went vegan, when we dropped our first book, there were basically no vegan meats out there other than, for instance, Linda McCartney sausages – and even they were relatively scarce, you’d have to get them in a big supermarket,” Theasby says. “But now in all supermarkets, especially here in Europe, they’ve got hundreds of meat analogues.”

And the industry is growing, with supermarket Tesco pledging a 300% increase in its sales of meat alternatives by 2025.

Attitudes have changed too. “There’s been a paradigm shift in the United Kingdom,” notes Firth. “Eight-and-a-half years ago, it [veganism] was weird, it was new, it was very esoteric. It was generally a female thing, eating vegan food, and I think that’s changed completely now – all of those things have mostly been normalised.

“So it’s now perfectly acceptable to eat a vegan meal, rather than having to eat every single meal vegan. There’s a lot of ‘dipping their toe’ vegans who will have a vegan day a week, or a vegan morning, or a vegan evening or whatever. It’s no longer weird, it’s no longer esoteric, but also – it’s now understood all across the UK, doctors will confirm that it’s very healthy to eat a plant-based diet.

“Particularly if you’re older and you’re starting to think about the big diseases that affect humans, a well-planned plant-based diet is an excellent way to fight against those. And that’s very medically found now – eight years ago, doctors wouldn’t have said that.”

However, the duo suggest misconceptions around veganism haven’t completely gone away – particularly when it comes to conversations around ultra-processed foods. These are foods which typically have five or more ingredients and a long shelf life, and vegan meat replacements are often labelled as such.

“I think the term ‘ultra-processed’ is useful if we’re using it to examine all of the foods we eat on a daily basis,” says Firth.

“Absolutely the best thing we as humans can eat is plants, whole foods, foods that look like the original food and that don’t come in a packet. I think where the term ‘ultra-processed’ becomes a problem is where it’s mostly used at the moment, which is to talk about vegan meat. Because actually, the process by which these alt meats are made is fairly similar to how bread is made.”

Firth suggests unconscious bias against plant-based food is at play, and we need to “make sure we’re applying the same level of scrutiny to all foods, otherwise it’s just another way to criticise vegan food”.

So where do the brains behind Bosh! see veganism going next? For Theasby, it’s all about innovation.

“There is some really fantastic innovation going on in the plant-based space,” he says.

“There are new raw materials being used – rather than soy, people are using things like fava beans, which are really high in protein, and get fantastic new methods of extrusion [the method used to create meat substitutes], which is making that fantastic texture you have in plant-based meats.” This is Bosh!’s sixth cookbook in five years, and it’s these innovations that help them come up with new dishes.

“We did get recipe fatigue after about three books,” Firth admits. “It’s tough, because each book you’ve got 100 or so recipes in, you do wear out your mindset and your favourites.

“But the good news is our minds are refreshed by the new ingredients that are coming onto the market – the fact that you can buy these meat analogues has opened up the floodgates for us… So it’s almost like every time we write a new book, there are new ingredients for us to play with – which helps fight that recipe fatigue.”

BOSH! Meat: Over 100 Outrageously Tasty Recipes by Henry Firth and Ian Theasby is published by HQ on August 17, priced £22. Photography by Lizzie Mayson.