Previously unseen letters have revealed Princess Diana's favourite meal and unearthed a hand-written recipe by former Prime Minister Margaret Thatcher.
A care home charity in Johannesburg, South Africa wrote to famous people back in 1981 asking for their favourite recipes for a new cook book.
Some wrote back, and their recipes were collected and put into a book by Avil Elizabeth Home for the Mentally Handicapped and sold locally.
The letters have now been rediscovered by a visitor to the home.
They include a letter from Princess Diana telling the charity her favourite recipe was hearty bowl of Ukrainian beetroot soup
The letter from her private secretary, Oliver Everett, said Prince William and Harry's mum liked her version of the bright red Borscht soup to contain "beetroot, yogurt, onion, chicken stock, milk, sour cream, salt and pepper."
Her letter, written on April 7, 1981 three months before her wedding to Prince Charles, was addressed to Mrs A Hopley.
And another letter from 10 Downing Street revealed Margaret Thatcher's personal recipe for orange and walnut cake.
It warned readers to "be careful not to overheat the icing when blending" and said the secret ingredient was a splash of concentrated orange juice alongside the rind.
The letters were found by Pauline Barnes, 60, when she got chatting to car home worker Angeline Hopley, who curated the cookbook.
Angeline was visiting a relative at the care home and enjoyed the letters so much she sent them to her son Michael Stanley, 39, from London.
Training director Michael said: "It's only a local charity in South Africa and the book will have only been sold in the community.
"These letters will have never been seen before.
"They sent lots of letters out to famous people and Princess Diana and Margaret Thatcher were two of the people who responded.
"It's nice to see they reached out to a small charity.
"South Africa is a former colonial country and the Royal Family is popular in the country."
The Cook's Book also contained the favourite recipes of Princess Grace of Monaco and the wife of Marais Steyn, South Africa's UK ambassador.
But one of the few who refused the charity's request was Queen Elizabeth The Queen Mother.
A letter from Clarence House, dated March 26 1981, said it's "not possible" for her favourite meal to be publicly released due to official rules.
Michael added how he found it funny that the Queen's mother refused to give her recipe and has praised the Royal Family for spending the time to reach out the charity.
He said: "It is funny that Queen Elizabeth wouldn't send her meal.
"The reason seems very secret and I do wonder why.
"Both recipes are very interesting and very different.
"I like how Princess Diana's is a humble dish. You'd expect the Royal Family to eat posh meals but this is very basic.
"It's great they got back to the charity, it was a nice thing to do. It was a charitable issue.
"The Royal Family are always very well received in South Africa and I'm sure this went down well."
