Royals British Royal Family Prince George, Princess Charlotte and Prince Louis Bake for Kate Middleton on Mother's Day in the U.K. The Cambridges are paying tribute to Kate Middleton and her mother Carole By Stephanie Petit Stephanie Petit Stephanie Petit is a Royals Editor, Writer and Reporter at PEOPLE. People Editorial Guidelines Published on March 14, 2021 11:20AM EDT The Cambridge family's 2020 Christmas card. Photo: Matt Porteous / The Duke and Duchess of Cambridge/Kensington Palace via Getty Happy Mother's Day, Kate Middleton! In honor of the annual holiday, which is known as "Mothering Sunday" and celebrated in the U.K. this year on March 14, Kate and Prince William — who are parents to Prince George, 7, Princess Charlotte, 5, and Prince Louis, 2 — shared a photo of the cake their kids made. "Celebrating two other special mothers today ❤️ 🎂 made by George, Charlotte and Louis," the caption read. Along with the image of the homemade cake, a throwback photo of Kate and her mother Carole Middleton was shared. To celebrate the holiday last year, the parents of three shared a previously unseen photo on social media showing Princess Charlotte and Kate sporting matching smiles as the little royal rides on her mom's back. In the background, Prince George can be seen enjoying a piggyback ride from dad William. The photo was actually from fall 2018, when the Cambridge family gathered for their annual Christmas card photo at their country home in Norfolk, Anmer Hall. Their post also included a photo of William with younger brother Prince Harry and their late mother, Princess Diana, as well as a throwback image of Kate with her mother. Finally, the parents shared a sweet card made by Prince George for his mom. Kate Middleton's Cutest Mom Moments with Prince George, Princess Charlotte and Prince Louis Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! After spending much of the year at the country home during lockdown, the Cambridge family recently returned to London, as schools have reopened. Prince William and Kate Middleton. JUSTIN TALLIS/AFP via Getty Images Get the premiere issue of PEOPLE Royals for glamorous new photos and inside stories royals fans haven't seen or read elsewhere! Subscribe at peopleroyals.com/launch On Thursday, Kate and Prince William stepped out in London to congratulate teachers involved in the re-opening of their school following lockdown. During the outing, Prince William spoke out against claims of racism within the royal family made during Prince Harry and Meghan Markle's sit-down interview with Oprah Winfrey on Sunday. "We are very much not a racist family," as he and wife Kate Middleton stepped out for the first time since the royal family was stunned by the interview. When asked if he had spoken to Harry after the Oprah interview, he added, "No, I haven't spoken to him yet, but I will do."