"I didn't know if we were doing the right thing and was so anxious I found it hard to sleep.
"But getting to this point now is really cool. I know we made the right decision."
Since MasterChef, the pair have been flat-out busy - working on their food column for Living and flying round the country to events, as well as creating a unique and beautiful cookbook that not only shares their food secrets but also gives a glimpse of all that's most important to them.
"It's more than a cookbook, it's a story of our lives," says Karena, 24.
"We brought the photographer [Deborah Aspray] to Maketu and she stayed in one of our family homes, ate dinner with us every night and took pictures of us doing everyday things.
"There are shots of us cooking together or with our family having morning coffee and scenic shots of Maketu. So really it's a storybook of where these dishes come from and how they make us feel.
"And I guess it's also about how unique and special small-town New Zealand is."
The sisters admit they were concerned they wouldn't have enough ideas to fill a whole book.
"We haven't really been cooking for very long," points out Karena.
"It's not like we've been in the food industry for years and have all these recipes to choose from. So we sat down and wrote a list of every dish or meal we eat on a regular basis - things we've grown up with.
"By the time we finished, we had about 100 recipes and we culled it down to the 75 we liked the best."
Online research helped them track down Aspray, whose work they loved, then the sisters spent time poring over books.
They contacted designer Kate Frances, who they realised had worked on many of the books they liked best. She in turn put them in touch with editors she'd worked with and gradually a small community of talented people came together to create For the Love Of.
"We flew down to Christchurch and shot 80 per cent of the book," says Kasey. "We'd had a full-on year but I reckon that was the hardest 10 days I had experienced, just shooting recipe after recipe."
Such an intense working relationship might create tension in some families, but Karena and Kasey promise that hasn't been the case for them. "We still haven't fought or anything," says Karena. "We don't always agree on things but we never get angry, we stay reasonable and discuss it."
"Actually, we're way closer," adds Kasey. "I've got a greater appreciation for our relationship. We've worked so well together and I think it's because we're so different.
"Karena is more outgoing than me.
I wouldn't be able to do what we've done without her. It's not in my nature. Even with the book I'd rather go along and keep everyone happy. It's Karena who says, no, no, no."
Kasey's shyness made her an unlikely MasterChef contender in the first place, never mind a winner.
"Not that long ago I found it hard to talk to people on the phone," she admits.
"Even just calling for an appointment to get my nails done I'd get really nervous and hang up. I'd have left MasterChef that first day if Karena hadn't been there."
And anyone who witnessed Karena's early experiments with food wouldn't have pegged her as a cooking show contestant.
"The first thing I remember trying to make involved a frozen ball of raspberry jam coated in Milo. I put it in the microwave and it exploded everywhere!"
The sisters grew to share a love of dining out and exploring different food styles and that inspired them to try to recreate the flavour themselves.
They became keen home cooks but when they landed the MasterChef audition their father, Kerry, told them not to do it. He was concerned it was too much of a risk and would distract them from careers and study.
"He said we'd never cooked for anyone but our families so didn't know if we were any good," says Karena.
His words motivated them to take the challenge more seriously and they set up a study plan, swotting up on different cooking techniques each day and pop-quizzing each other about food.
"In our bedrooms we had all these diagrams of beef with its different cuts, and folders full of things we could make with them," recalls Karena. "We worked really hard at it."
The sisters credit their parents for their impressive drive and ambition.
"They've never let us take shortcuts," says Karena. "Everything you do, you have to do properly, that's just how we were brought up."
"They've always had high expectations," adds Kasey, "which I think makes you have high expectations of yourself.
"We don't do anything by halves and that's reflected in our book. It's this big hard cover with gold foil on the front, two ribbons and really good quality paper."
For the Love Of is divided into very different chapters. Family recipes are shared in "For the Love of Whanau", easy weeknight dinners in "For the Love of Everyday" and more aspirational restaurant-style dishes in "For the Love of Glamming It Up".
"We're still learning and evolving so I don't think we're about one particular thing yet when it comes to food," says Kasey. "But every recipe has the same sort of wairua [spirit]."
For the next few months the sisters will be busy promoting their book. After that, the plan is to knuckle down and learn even more about cooking by doing time in a restaurant kitchen.
They have stayed in touch with MasterChef judges Simon Gault, Josh Emett and Ray McVinnie and have offers they're keen to take up. Their dream for next year is to travel and experience some of the best cuisines of the world.
"We'd like to learn about Italian food in Italy and French food in France," says Karena.
"That's the purest way of learning. We've had no formal training and I think that's why there's such variety in our cooking. But we'd love to learn the proper ways to do things and combine that with our free-styling ways."
When they've had a taste of the rest of the world, their goal is to come back to New Zealand and open a restaurant.
"It's a tough business and we want to get it right. That's why we're not in any hurry to do it," says Karena.
Maketu is where they will always return to rejuvenate. However, work is increasingly taking them to other places. It's a wrench to leave home and family but both are still amazed and thrilled at the opportunities MasterChef is opening up for them.
"Food is our obsession," says Kasey. "Creating recipes and testing them is just so exciting. It's awesome to wake up and feel excited about what you're doing."
Adds Karena: "We just sit there sometimes and think: 'We can't believe this is what our lives are like and this is what we do now'."
Win
Lunch with Kasey and Karena
You have the chance to enjoy a sumptuous lunch with Kasey and Karena Bird to celebrate the launch of their new book, For the Love Of. . . One lucky winner and three friends can win a feasting lunch with the Birds at Molten restaurant in Auckland's Mt Eden. Turn to page 14 to see part of the menu. The date of prize redemption is by arrangement and does not include transport to Auckland, transfers or accommodation.
To enter, visit winwithheraldonsunday.co.nz and enter the key word 'Feast' along with your contact details. Entries close 5pm on Wednesday, April 15.
