Gyngell left Australia at 18 to study at La Varenne​ cooking school in Paris, then landed apprenticeships in London's top kitchens before a phenomenally successful tenure at the Petersham Nurseries Cafe. The dirt-floored outpost scored a Michelin star for Gyngell's unfussy, seasonal food before she controversially quit in 2012. Three years later, the handsomely backed Spring at Somerset House offers Gyngell a chance to achieve everything she dreamed of at Petersham, and more.

"I said to Briony I want [Spring] to be beautiful, I want it to be feminine, I want it to be strong, I want it to be different to every other kind of West End restaurant, which are very chocolate-brown, male-driven, big-suited, booted, blokey places and I didn't want that. She literally took my dream and made it real."

Spring is certainly dreamy. It's an expansive series of grand, neoclassical rooms lovingly elevated with soft sorbet hues, festive glass light fittings, linen-clad tables and caramel leather chairs. There's a sparky, female-led army of staff on the floor, wearing haute couture Maureen Doherty uniforms that have generated much buzz and derision – somewhat pirate-like Breton striped tops, linen vests, voluminous aprons and rolled up trousers. It's fun, costumey and perhaps a bit pretentious, but undeniably enchanting.

Gyngell has little trace of her Australian accent. "I've just been in LA for a week and I've come back SO happy to see everyone," she says in a West London clip. At 51, she speaks like an excited teenager despite directing 68 staff and no fewer than 22 chefs. "I've got this little boy called Will T in the kitchen – he's gorgeous, he's 24, he's been in a lot of trouble and done quite a lot of jail time but went through the Jamie Oliver program. He's got a little girl and he's covered in tattoos and stuff like that. When he first came into work I thought, 'Gosh this is really scary', but now I love him SO much."

It's understandable Gyngell might give someone a second chance – she's had a few herself. Growing up in Sydney's affluent eastern suburbs, the daughter of Bruce Gyngell​, the first man to appear on Australian television, and legendarily glamorous interior designer Ann, Gyngell was uncomfortable with her famous surname. The family, including her brother David, the current Nine Network CEO, lived in mid-century modern grandeur eating a macrobiotic diet way before it was a thing to do. She was expelled from Ascham School at 14, spent 20 years battling heroin, and managed to come out the other side. For all her air of teenage enthusiasm, there's a hardness about Gyngell too.

"I am very tough in the kitchen. In that lunch service just now I was an absolute monster."

Gyngell says she sometimes feels paranoid people see her as "difficult". "I'm very mercurial, I'm very hot-headed, and I'm quite passionate, but I blow over very quickly," she says. "I'm quite full on. Really. I realise now I'm strong, and I'm opinionated, and I don't think that's a bad thing. I'm not criticising myself for that. But I also have shortcomings around that."

In 2012, after being named Australia's first Michelin-starred female chef, she caused a storm of controversy, describing the accolade "a curse", and promptly hanging up her chefs' whites. Why did she leave?

"When I got [the star] ... I cried, I was so thrilled, and so, so, so excited. And still, I'm so proud I got a Michelin star, I can't tell you, I really am. But [saying it was a curse] was a really off-the-cuff statement and I didn't hand the Michelin star back, I didn't leave because I got a Michelin star. I left because I had been there for nine-and-a-half years and I was cold. In the winter, I was! I was cold. And I'd gone as far as I could go."

Certainly, receiving the accolade heightened expectations and attracted more stars such as Madonna and Mick Jagger. "You're doing this thing because you love it and it's fun, and then all of a sudden people come through the door saying, 'You're kidding me. A dirt floor? This chair is wobbly! This chair is wobbly!'

"And then they say this classic [line], 'You call yourself a Michelin-starred restaurant?' And like, no, no, we didn't call ourselves a Michelin-starred restaurant. And rather than people coming to you with an open heart and no expectations, all of a sudden you're on a tick list."

Gyngell rakes her blonde hair back behind her ears, pale face scrubbed and gleaming. She's fired up. "And people have perceptions – like I did – of what Michelin was and when you don't meet up to it … it's really…" She trails off, exasperated. It's hard to imagine someone as utterly fabulous as Gyngell would care what people thought. "I went through a year of real crisis after it happened, and I lost a lot of confidence, and it was nothing to do with Michelin."

In a flicker it seems like a penny drops and Gyngell realises she'll never escape criticism, or accolades. "I've done it again in the West End! I mean I should have stayed away in Petersham ... Or come back to Australia!" This last remark is clearly a joke –  after 30 years, it's unlikely she'll move back. "Every time you open yourself up to something, you open yourself up to criticism."

The reviews for Spring have been mixed. Mostly glowing, but not always –  it's too much fun to tear down an ambitious, idealistic, and prohibitively expensive restaurant such as Spring.  "Did you read the Camilla Long review in The Sunday Times?" Gyngell asks incredulously, but in good humour. "My God, don't read that one … she called Somerset House an ugly 'bean counting' building – I mean, I don't know how anyone could say this. And then she called these –" Gyngell motions to a stunning ice blue wall adorned with thousands of white shards blown across the surface like migrating birds. "These are 5800 ceramic blossoms by a Brazilian artist called Valeria Nascimento​! Aren't they so beautiful? She called them menopausal sodden tissues thrown against the wall. That was her wording … She called my food bile! I got away lightly, I just got one sentence. I woke up on the Sunday morning [it was published], and it felt like acid in my face for a moment, but then it really worked for us in a funny way."

Despite endless musings about the Somerset House fitout, or the uniforms, or the dreaded Michelin star, or Gyngell herself, the heart of Spring is the wonderful, seasonal, produce-driven food.

"We make everything here, completely. All our tonics, kefir​ butter and the breads, all our yoghurts we make here, the labna​ on the menu today was all made here. All those drinks on the bar, the limoncello is made here, the digestifs, the ice-creams – all made here."

There's something terribly seductive about Gyngell when she's talking about fresh produce, rolling the names of each fresh ingredient off her tongue as if to taste them. "Today, we've got wild garlic, broad beans, asparagus, we going to have a mango and strawberry ice-cream on tomorrow. I only work seasonally. I wouldn't even contemplate the alternative."

Gyngell cooks visually, and says she needs to see the ingredients before committing to a menu. She's constantly experimenting in the kitchen – today's bruscandoli (hop shoots), broad beans and wild asparagus with halibut is something she's never made before. "You can't go wrong, nothing clashes in season. It's kind of like we're all born with the perfect eye, hair, skin colour. We like to squiddle it all around a bit, but nature is amazing."

Spring is more than just a restaurant. Expansion plans include a cooking school, a shop, an edible garden, and even a Hare Krishna-style canteen ("But chic …" promises Gyngell). She has brokered an agreement with boutique biodynamic farm Fern Verrow to use all its produce, in both summer and winter, in an effort to be more sustainable, more viable, more creative. There's an activist in her.

"Once you get me talking, I'm so sorry, I don't stop," Gyngell says, truthfully. Then she swerves on to the next thought. "I saw something on Instagram the other day that someone put up about the Dalai Lama. It said, 'If you think you're too small to make a difference, think of the effect a tiny mosquito has in a room.' And I thought YES. That's so true, isn't it?"

Image extracted from Spring by Skye Gyngell published by Quadrille, RRP $55. Available now.