The super affordable secret ingredient behind Queen Elizabeth's favorite sandwiches at Buckingham Palace

The Queen was famed for her love of cucumber sandwiches, but you might not have known that the late monarch's favorite snack contained a secret ingredient.

• The late Queen Elizabeth's favorite cucumber sandwiches contained a secret ingredient that you can easily pick up at your local store.
• A TV presenter revealed the added ingredient while discussing having afternoon tea at Buckingham Palace.
• In other royal news, this is the color that Kate and William prefer to match in.

The late Queen Elizabeth reportedly observed the tradition of eating sandwiches at 4pm every day for the past several decades. 

Her sandwich of choice was cucumber, and it's now been revealed that those cucumber sandwiches contained a key ingredient that you can easily get your hands on - and it's budget-friendly.

TV presenter Jenny Hanley opened up about enjoying the famous afternoon tea at Buckingham Palace, explaining, "The most wonderful thing that happened at one of the Buckingham Palace garden parties that I was lucky enough to go to was not the fact of the scones but the cucumber sandwiches."

She added, revealing the key ingredient, "They may be a joke to some people, but when you've had a cucumber sandwich out on the grass at the back of Buckingham Palace and the sun is shining and there's mint in it, then you know you've made it!"

"I will never make a cucumber sandwich without chopped mint in it again," she added. It was revealed that the sandwiches were made with buttered white bread, sliced cucumber, a “dash” of mint and a pinch of pepper.

The Queen was very particular about her afternoon tea and had a specific order, which was revealed by former royal chef, Darren McGrady.

He said, "The Queen loved afternoon tea, I would say it’s probably one of her favorite meals." He also confirmed that she never missed it – regardless of her location or commitments. 

"The Queen had afternoon tea every day, wherever she was in the world," he said. "If we were at Buckingham Palace and she was on her own for tea, or whether she had Prince William come and join her, or whether she had a garden party for 6,000 people, or even if she was on the Royal Britannia in Australia." 

As for what the Queen liked to eat during these afternoon teas, it looks like she had quite the penchant for the menu's sweeter bites. McGrady explains that, while the royal matriarch was 'frugal' and 'by no means a foodie', she refused to deprive herself of her chefs' baked treats. 

"Every day, she would have what we called a 'cut cake’ – meaning she would cut a slice of it off – small cakes like eclairs or raspberry tartlets," he told the Telegraph. 

The Queen also had a strange request when it came to scones, insisting that the same flavors were never served two days in a row.