The royal chef now has his own YouTube channel with over 68,000 subscribers, where he shares his cooking secrets, including dishes that were loved by the royals.
McGrady often includes sweet anecdotes about his time serving the queen – making it a great place for royal fans to discover new recipes and insights into the inner workings of the family.
In a recent video, the chef revealed the secret ingredient for traditional Scottish shortbread, a treat he used to make for the Queen when she visited Balmoral.
Shortbread recipes usually use flour, butter and sugar, which the chef said can be granulated or powdered.
However, for the Queen’s Balmoral recipe, McGrady added corn starch to the ingredients.
He explained that this softens the shortbread so that instead of snapping like a biscuit, it crumbles and melts in your mouth.
He also used a special mold for the recipe to make it look traditional, just like it would in Balmoral.
The mold featured a thistle design, which is the floral emblem of Scotland, in a rounded shape – though you can simply use a cookie cutter if you prefer.
To make the shortbread, McGrady took eight ounces of flour, eight ounces of butter, four ounces of corn starch and four ounces of sugar and mixed them in a bowl by hand.
The chef advised viewers to rub them all together until it’s a crumb-like consistency, before adding the vanilla paste which will add flavour.
It can then be pressed into the mold (or cut into shapes) before being put onto parchment paper on a baking tray.
But before he put it in the oven, the chef took a fork and pierced the top of the shortbread all over.
This is so that as the shortbread bakes, the heat will go to the base and help to cook it faster.
It can then be popped in the oven for around 20 minutes on 350 degrees until it’s golden brown – but there’s an important step if you don’t want it to crumble.
The chef explained that you must cut the shortbread into slices, if you’ve used the mold, while it is still hot.
But he showed a special technique of just cutting a third of the way through, rather than all the way to the base.
Once it’s cooled after about an hour, it can then be carefully broken into pieces without crumbling, ready to be served with a cup of the Queen’s favourite Earl Grey.