Despite holding the record for the second-fastest-selling non-fiction book in the UK since records began, Kate and Kay Allinson – the brains behind Pinch of Nom – are relatively private people.

They don’t do many interviews and you won’t see them whipping up a storm on daytime cooking shows, yet the duo seem remarkably comfortable fielding questions about their latest cookbook, Pinch Of Nom: Budget.

Kate, 52, is the softer-spoken of the two – she’s a trained chef – while Kay, 37, is more outgoing and talkative. The two have been together for 18 years and married for two.

Their clashing personalities might come as a surprise, but they make it work – for example, by having two freezers.

“One is my freezer, one is Kate’s – there’s a big difference between the two of them,” Kay says matter-of-factly.

“I’ve got ADHD, so she has to put up with a lot. Kate’s the tidy, organised one – if I put it this way, if I’m putting the food shopping away, she’s like, ‘You’re not putting the food shopping away, I’m putting it away, because it’ll go away in some sort of order’.”

Kay works with “lots of noise, lots of mess, lots of creativity, disorganisation”, she admits. “And Kate is the polar opposite – everything has to be quiet, everything has to be neat and tidy. I think it works because we complement each other in different ways.

“You [she says to Kate] make sure I actually get through the day without harming myself, and I give you the ideas – so it works.”

The two have made an empire with their healthy cookbooks. The first Pinch Of Nom cookbook came out in 2019 and sold 210,506 copies in the first week – the only non-fiction title to outstrip that is Spare by the Duke of Sussex. Their fanbase is loyal, and they have 1.2 million followers on Instagram – but don’t call them diet books (Kay doesn’t use the d-word, saying: “I hate it”.)

Now, the duo are releasing their first book specifically geared towards wallet-friendly recipes – which felt like a natural progression.

“Most of the recipes we’ve ever come up with, one of the main goals – apart from it being actual food you want to eat, because that always helps when you’re making a recipe book – is they’re easy to make, but also that they don’t break the bank,” Kay says.

Kate adds to that thought: “Given our audience from day one, our audience has always been very family orientated.”

“And running a family is expensive enough, especially at the minute – thank you Brexit,” Kay sighs. “Food inflation is not fun for anyone at the minute – it’s ridiculous out there, it’s crazy. The amount of people that rely on food banks – food poverty is a really big issue.”

While there are no price guarantees with their recipes, most dishes come to under £2 to make and many cost even less – busting the misconception that healthy eating is expensive.

“Whatever it is, you can make it expensive – there’s ways and means to do things,” Kay says.

“If you want to do healthy food organically, it’s not going to come cheap. If you want to go to Daylesford Organic for your food, that’s fine. But most real people that live on a day-to-day basis will shop at one of the big four supermarkets or the big two discounters. We all know who they are. And we want people to be able to buy all the recipes and the ingredients in one place and not have to traipse around everywhere.

“We want to make it as easy as possible – people are time-poor. Maintaining a family and making sure everyone is fed and looked after is hard enough – the last thing you need is to traipse around the big posh supermarket trying to find weird ingredients.”

This could be the couple’s secret to success – they’re refreshingly normal, and even talk about their own “bumpy journey” with healthy eating.

“We said last week, we’re going to meal plan all week – what didn’t we do? We didn’t get round to cooking the meals, because we’re busy doing other stuff – because that always happens,” Kay says – but all wasn’t lost, because they used their number one tip for keeping healthy and saving money: the freezer.

“It’s always handy to have something in the freezer or in the fridge that on that day when you come home from work and you cannot be arsed – everyone has that day or that week. To be fair, it’s usually a couple of days,” says Kay.

“Getting something out of the freezer that you know is going to taste good, you only have to heat it up – you don’t have to make it. Just having that reassurance that you can fall back on it.”

Kate and Kay estimate there are around 3,000 Pinch of Nom recipes, created by themselves and their team. With such a vast number, do they ever get writer’s block?

“We do get stuck for inspiration, quite often,” Kate admits – and in those scenarios, their first port of call is going to the Facebook group “and look to see what people want”.

Kay jumps in: “We’ll ask them what they want to see. I used to post every week in the Facebook group without fail, ‘OK, tell us what dishes you want. What do you want a Nom version of?’

“Don’t get me wrong, there were some ridiculous requests – there is no way the chocolate cake from Matilda was ever going to be Nommable, that is just not going to happen. As much as I would love to be a magician and I would love for that to be real.”

Other suggestions are a bit more feasible – and they’ve seen a big rise in demand for veggie recipes.

“A lot of people – we’re the same, it’s not that we don’t like meat, but we’ve made a conscious choice to eat less meat, mainly because of cost. Meat costs a fortune, and if you can get your protein from plants, then yay – it’s a good thing,” Kay says.

“So we’ve had an awful lot of veggies recently, or people just wanting to cut down on meat – and I’m assuming it’s because it’s friggin’ expensive.”

Another trend that will never go away? “We still get loads of fakeaway requests,” Kay says. “Fakeaways are never going to disappear, ever.”

Kay adds: “We like to give people a decent amount of stuff that isn’t quite as calorific as it would ordinarily be, but enough so you have something to look forward to in the week. Everyone needs a bit of a treat, because it’s no fun – when people think of diets, they think of lettuce. I do, and I’m like – it’s a bit boring. Sod that.”

Pinch Of Nom: Budget by Kate and Kay Allinson is published by Bluebird, priced £17.99. Photography by Ellis Parrinder. Available now.