“Celebrating two other special mothers today,” the caption stated, presumably referring to Wills and Kate’s mothers: Diana, the late Princess of Wales and Carole Middleton.
The sweet sponge cake, which featured generous layers of butter icing and jam, was topped with colourful chocolate buttons, hundreds and thousands and homemade heart cake toppers.
An accompanying caption added: “Made by George, Charlotte and Louis.”
Enthusiastic fans were quick to take to the social platform to comment on the cake, with one person writing: “George, Charlotte and Louis you’d get a handshake from Mary Berry!”
Another person stated: “Just fabulous! Happy Mother’s Day to all concerned and just thinking about all those people who can’t be with their mothers or children today.”
Meanwhile a third person added: “How lovely and thanks for sharing this beautiful photo of the Duchess of Cambridge with mummy,” referring to a follow-up snap.
The Cambridges’ adorable update comes after the Duchess previously showed off her culinary prowess in the TV special, A Berry Royal Christmas, alongside TV chef royalty Mary Berry.
Kate and Wills had teamed up with the cooking legend, and her fellow Bake-Off star Nadiya Hussain, to celebrate hard-working volunteers who work tirelessly through the Christmas period.
The royal couple later shared a carousel of images from the show, along with a heartfelt message, explaining why they opted to partner up with the cooking pros.
“The Duke and Duchess of Cambridge have joined forces with cookery legend Mary Berry to prepare festive food to thank all those working and volunteering over the Christmas period,” the message stated.