Their book is outselling Jamie and Nigella – but foodies are horrified by their four-ingredient recipes. Tanith Carey meets the Australian housewives who believe home cooking needn't be either complicated or time-consuming

There can be no more fitting successors to Dame Edna Everage's crown of Australia's Housewife Superstars than Kim McCosker and Rachael Bermingham. For a start, the "Queensland Battered Vegetables" from their best-selling 4 Ingredients cookery book, can so easily be imagined served on Tupperware canapé trays in Moonee Ponds.

On the Chris Evans radio show, the pair are cheerfully – if tunelessly – singing along to the Aussie national anthem and calling everyone "Darl". They are also chattering in true Dame Edna hyperbole about how they have "miraculously co-authored" the book, which over the last two years has sold a more than a million copies Down Under and has now shot to the top of the UK Amazon charts, currently out-selling the likes of Jamie Oliver and Nigella Lawson.

The reason the real housewife superstars – actually from Pelican Waters, Brisbane – are in the UK is to spread to their message that four ingredients is all it takes to make wholesome family meals. "Aw, Darl!" says Bermingham later. "You know, we can't believe we're here either. We just can't believe that our little book has brought us to L.O.N.D.O.N. We have to keep pinching ourselves! McCosker chimes in: "But when you try our pineapple cake – a tin of pineapple slices, some self-raising flour and sugar –you'll see why, because it's yummo!"

Indeed, a browse of the the book instantly confirms that most of the recipes generally contain more exclamation marks than ingredients. Most gastronomes would certainly turn up their noses at the book's folksy descriptions – "a real crowd-pleaser!" and "Sooooooo delicious!" By comparison, the back-to-basics-cookery hit of the year, Gill Holcombe's How to Feed your Whole Family, starts to looks like haute cuisine.

Each recipe is also no more than four lines long – and there's not much weighing or measuring either. The other essential is that all must use easy-to-buy ingredients most people already have in their kitchen cupboards. Already, the book has sharply divided opinion. Food lovers see it all as sacrilege. A reliance on canned soups for flavouring and shop-bought sauces understandably attracts criticism that there is some cheating going on here. As one exasperated reader splutters: "Nonsense! It shouldn't be called the name anyway! Cookies and Cream Truffles using 500g of Oreo cookies?" Another reviewer rants: "Take for example the korma chicken – the four ingredients are chicken, two carrots, freshly chopped coriander AND a jar of Korma sauce!"

But Bermingham and McCosker argue that if comes out of a single packet, it qualifies as a single ingredient –and if you are a mum in a rush with hungry mouths to feed, you won't care. And anyway, who can argue with the sales figures? To date, the book has sold 1.4 million copies in Australia, where an impressive one in ten households has a copy. Now it's poised to join the UK bestseller list after hitting the number one spot in our Amazon chart within a week of the authors' arrival. TV production companies are also queuing to sign up their brand of brassy Australian optimism.

All white teeth, blonde highlights and golden tans,they do indeed make a great double act. To listen to their relentlessly upbeat offerings on life and food, it's almost impossible to tell them apart. The childhood friends, both in their late 30s and with four young sons between them, had their Eureka moment over a glass of red wine at a family barbecue three years ago. McCosker, who was working as a financial planner, says: "I happened to mention I had an idea for a book. She said: 'What's that, Darl?', and I told her that for years, I'd been collecting recipes which needed just four ingredients. She screamed; 'Oh my God! I would buy that book. You have to write it.' It just shows more mums should talk over ideas over a few glasses of red wine!"

The pair then set about emailing friends and family to collect more recipes. The hardest part, says McCosker, was testing them themselves. "We are not cooks, so it was torture. We had to cook 1000 recipes to get it down to the final 340." Cannily, they also recognised that after a long, hard day, people who are not natural cooks are in no mood to get their heads round complex instructions. "So we wrote it punch, punch, punch, punch. All no more than four sentences. And there you go. The meal's in the oven," says McCosker.

The pair were convinced there would be a market for the book because everyone they mentioned it to said they would buy it – even without glossy, art-directed pictures of the dishes. But then every publishing house they tried turned it down. McCosker says: "When we'd ring, they would say, 'Are you famous? Are you chefs?' We'd say 'No', and they would hang up. That was a shock."

So they remortgaged their homes, self-published and followed it up with a ruthless marketing campaign that proved that,behind the self-styled "Aussie chicks from the Sunshine coast" image lie two sharp-eyed businesswomen. They rang up every single bookshop in the country, and organised more than 600 book signings and appearances. At each, they put out tables with platefuls of food to prove the recipes worked – and also made sure there were crèche facilities so time-pressed mums could come too.

Back in Oz, where they are household names, the second volume of 4 Ingredients has already sold half a million, a second TV series is about to be aired, and there are plans for gluten-free and dinner party editions. As the publishers, too, they have also reaped virtually all the profits, enabling them to pay off their mortgages, and allowing their husbands, Glen and Paul, to quit their jobs to get on board the family juggernaut.

Industry watchers have been amazed – especially as the idea is far from new, although the authors didn't realise it at the time. A quick browse on Amazon reveals at least 40 other long-forgotten books with the same concept. The difference of course is in the timing – and the gusto with which the two have promoted the title. In an era when people are time-crunched as well as short on money, yet anxious to avoid the stigma of convenience foods, the book has found a receptive audience. Sales figures show it sells not just to busy mums, but to single men and students, too.

Literary agent Heather Holden-Brown, whose authors include several well-known cookery writers, believes the success of the book is a natural extension to the movement symbolised by Delia's How to Cheat at Cooking. "I would say this is a reaction which has been brewing for some time. Although chefs like Jamie Oliver and Gordon Ramsay have done a lot in recent years to make their cookery accessible, there is still this crazy gap between who will try their recipes and those who are still too daunted by them. Cookery is not taught in schools so there remains a generation of people out there who still feel hugely intimidated. As a result, publishers are commissioning new authors who are taking it back to the bone, like Tiffany Goodall, a student who saw a gap in the market to teach other students how to cook. Like Tiffany, the 4 Ingredients women probably feel like a breath of fresh air."

Bermingham and McCosker certainly feel they are benefitting from the backlash, and say their biggest selling point is that they are ordinary women – not posh, Oxford-educated sex kittens or Michelin-starred chefs.

But while it's heresy for some, for those who aren't cooks, the recipes are satisfying and the book's clever marrying of flavours – often inspired by Aussie barbecue cooking – works well. "We aren't for an instant espousing this as the be-all-and-end-all in the kitchen," says McCosker. "What we are saying is that if you are like us, if you are busy and want to save some time and money then there is an excellent chance you will enjoy the recipes in 4 ingredients. Of course, Nigella has her time and place.But we simply didn't have time in our everyday lives to be trotting out the glossy cookbook with 16 ingredients, half of which I didn't have – and half of which I had absolutely no idea where to get at 5:30pm in the afternoon after soccer when the kids are starving. Somewhere in all of it, we over-complicated things. We forget that sometimes it's the simple things in life that are truly the greatest."

Beef stir fry

500g stir fry beef
cup bbq sauce
3 tbs sesame oil
4-6 shallots, chopped

Marinate meat and sauce together for at least 15 minutes. Heat oil in a wok or frying pan. Stir-fry meat in batches for one to two minutes, or until cooked on the outside and medium on the inside. Trim the shallots and cut into thin lengthwise strips, add to meat and stir-fry in wok. Serve on top of a salad (even just shredded ice-berg lettuce is nice) and top with jus.

Pot pie

500g lean mince
250g jar fruit chutney
Half an onion, peeled and finely chopped
Half a sheet of puff pastry

Preheat oven to 185C. Place the onion in a non-stick fry pan with a half cup of water and cook on medium heat for five minutes. Add mince and cook till brown, then add the chutney. Stir through till warm and spoon mixture into two pie-sized ramekins. Cut two ramekin-sized circles out of the puff pastry and top pie with each. Seal with a fork before baking for 15 minutes, or until pastry top is golden.

'4 Ingredients' by Rachael Bermingham and Kim McCosker, £8.99. To order this book for the special price of £8.50 (free P&P) call 0870 0798897 or go to www.independentbooks