The winning dish will be revealed in BBC's The Jubilee Pudding: 70 Years in the Baking, which is set to air on 12 May. The winner will be revealed by the Duchess of Cornwall, and the royal will be introduced by Dame Mary Berry, one of the judges for the show. The idea for Camilla's involvement came from the Eden Project, who launched the Big Lunch community initiative.
WATCH: See how the Queen's Jubilee has evolved throughout the years
The competition launched with the aim of tasking UK residents aged eight and above with creating a new pudding dedicated to the Queen.
The concept has been used before, with coronation chicken coming about for the coronation of the monarch, while the Victoria Sponge was named after Queen Victoria.
The entrants will be narrowed down to five finalists, and the decision will be made by five judges: Monica Galetti, the chef proprietor of Mere and judge on MasterChef: The Professionals; baker Jane Dunn; baker and TV presenter Rahul Madul; pastry chef Matt Adlard; and culinary historian and author Regula Ysewijn.
There were nearly 5,000 entrants to the competition, and they were narrowed down to the final five through a blind taste test, with Buckingham Palace's head chef, Mark Flanagan playing a role.
The Duchess will reveal the winning pudding
The idea came from Fortnum & Mason, and their executive pastry chef, Roger Pizey, and their chef director, Sydney Aldridge, also helped with the blind tasting.
Further details about the Queen's Platinum Jubilee were confirmed earlier this week, including the news of a four-act pageant marking key moments of her life.
The first act of the pageant will begin with the bell of Westminster Abbey being peeled as they were on the day of the Queen's coronation, before a 1,750-strong military parade will march.
The second act, which will feature 150 national treasures and will aim to highlight how British and Commonwealth creativity and culture has evolved throughout the Queen's reign.
The Queen is celebrating her Platinum Jubilee
The third act will be comprised of a 12-part play highlighting key moments of the Queen's life, as well as her personal interests.
Among the moments that will be featured are Her Majesty's marriage to her late husband, Prince Philip, as well as her coronation. It will also feature her love of animals with horses and corgis taking some central roles.
The finale will pay tribute to the monarch with a gospel choir performing to the sounds of the Band of Her Majesty’s Royal Marines. Members of the public viewing at home will be encouraged to join in, as the finale is led by Ed Sheeran.
Like this story? Sign up to our special Queen's Platinum Jubilee newsletter to get latest news, photos and videos related to Her Majesty's special milestone.