Dame Prue Leith may be TV royalty now, but one thing she says she’ll “take to her grave” is the shame of making the late Queen Elizabeth II a bad cup of tea.

“I couldn’t get out of the Palace how she liked her tea, so I ended up with a tray with all these options on it: silver teapots, a jug, bowls of lemon and different sugars, milk and cream – the Palace told me to just bring everything,” says the Great British Bake Off star.

It was 1975 at the opening of the Queen Elizabeth Conference Centre in London. The Queen finally reached Leith, who was carrying a rather heavy tray, after greeting a long line of dignitaries.

“I said, ‘Black or white Ma’am?’ She said black, so I put a piece of lemon in. She said, ‘No lemon’, so I had to fish the lemon out as I hadn’t got another cup – I didn’t know what to do with the bloody lemon!” the 82-year-old recalls. “Then I topped up her tea with water because most people who have black tea like it quite weak, and she said, ‘I like it strong’.

“So the poor woman got weak lemony tea when she likes strong black tea. I’ll go to my grave ashamed of it!”

These days of course, South African-born Leith is in her sixth series of Channel Four’s Great British Bake Off – “the best job in the world” – alongside Paul Hollywood, Matt Lucas and Noel Fielding, and has just published her latest cookbook, Bliss On Toast.

But the controversy garnered by some of the Bake Off episodes centring on cuisines of other countries, like  the recent ‘Mexico week’, has taken her by surprise.

“What we’re trying to do is celebrate other people’s cuisines, but we’ve only got three challenges, so obviously we’re not going to cover all the things that any country would want you to cover,” she says.

Describing the popular baking show as “tolerant, inclusive, encouraging and kind”, Leith adds: “I’m just sorry anyone was offended, because that’s not in the spirit of Bake Off.

“It does make you think, if [we cook] any foreign food and it’s not regarded as as a sign of appreciation and celebration, and imitation being flattery, then we’re in trouble, because British cooking has always been about taking other countries’ ideas.”

“Curry is supposed to be the most popular dish in Britain, it didn’t originate here. Most of our cooking techniques are French. Our supermarkets are packed with foreign ingredients. It would be the death of British cooking if we couldn’t help ourselves to other countries’ food.”

On a lighter note, the funniest part of being on the show, she says, is that she never understands the innuendos. “I’m just too old and my companions are like 15-year-old school children. They go into hysterics of laughter – you say the word sausage and they think it’s rude and I start like looking like a complete nana because I didn’t get the joke.”

It was a surprise to Leith – who married her second husband, retired fashion designer John Playfair, in 2006 – to even be considered for the job replacing Mary Berry back in 2017. “I thought, going to Channel Four, they’d want to change everything, but guess what? They found another old lady.”

She’d just finished 11 years as a judge on BBC Two’s Great British Menu and at 75 thought perhaps it was time to retire, but she couldn’t resist. Representation of older women on TV is improving, she agrees: “The ageism message must have got through.”

When it comes to British food though, nothing quite encapsulates it like a good old plate of toast (and maybe a correctly made cup of tea).

For Leith, Sunday night is the best time to enjoy it. “We’ve always had something on a Sunday night because Sunday night is like going back to school, isn’t it? You need comfort because you’re facing the week. So we’ve always had scrambled eggs and crisp bacon on Sunday nights, or mushrooms on toast, always something on toast – it’s comforting.

“If you’re feeling ill and you can’t eat anything, you can always eat a piece of dry toast,” she adds. “And then you get a bit better and you want some butter on it. The next morning it’s got marmalade on it.”

During lockdown, she’d find leftovers of her big chicken casseroles ended up on toast. “I began to realise that everything tastes better on toast.” So, in the book, readers can expect the likes of figs, blue cheese, thyme and honey on bloomer, Japanese chicken with katsu curry sauce on white toast and peppered steak and sala verde on sourdough.

Crucially, many are cheap to make. “We’re all very busy and we’re all worried about money and worried about time. Assembling something on toast is easy, stress-free and doesn’t have to be expensive,” Leith says. Her favourite – scallop Caesar on fried bread – is a little more special though.

“I never thought salad on top of bread would be good, but it is. For lunch, it’s just delightful. When you think of Caesar salad, it usually has croutons in it, so instead of having a fried croutons, I put a big fried piece of bread underneath.”

Many home-cooks won’t necessarily need a recipe for some of the combinations, and unlike baking, there’s no science to making great toast. “When I usually write cookbooks, I say to the readers, ‘Just trust the cookery writer and do exactly what it says’. Because many cooks make the mistake of thinking, ‘Oh well, if one tablespoon of sherry is good, three will be three times better’. But with this book, it’s more about ideas.”

After all, bread is having a moment. “The book opened my eyes to how many artisan bakeries there are now, and how even in supermarkets there’s a mass of different, really good breads,” she says.

“I don’t really expect the reader to have 20 different breads, but I do think it would be good if it encouraged them to buy ciabatta one week, focaccia the next week, a seeded brown…”

And in her early Eighties, Leith isn’t slowing down. She’s currently on one-woman tour around the US (coming to the UK next year), sharing her experiences. “People think of me as the woman on telly who eats cake for a living, which is true, but I’ve had a very adventurous life,” she says. When she opened her first restaurant, Leith’s, in 1969, she “was a woman doing stuff that was usually done by men” – earning a Michelin star in the process.

“People often say to me, ‘You’re amazing for 82’, and the truth is, I’m quite healthy, I eat well, I sleep well, I have quite a lot of energy. I think I’m just lucky,” says Leith.

And she’ll never tire of being called a a fashion icon, thanks to her colourful wardrobe and signature spectacles. “I love it,” she says, laughing. “I’ve always been a bit vain and very egotistical. ”

Bliss On Toast by Prue Leith is published by Bloomsbury, priced £14.99, photography by Haarala Hamilton. Available now. For tickets and venue info for Prue Leith’s ‘Nothing In Moderation’ UK tour (February 1 – April 6 2023), visit MickPerrin.com