It appears pizza is not on the menu when Kate Middleton and Queen Elizabeth get together.

The royal mom of three, who celebrated her 37th birthday last week, was peppered with questions from children during her visit to the King Henry’s Walk Garden in the London borough of Islington on Tuesday. As they made pizzas that would be cooked in an outdoor oven and talked about how fun it is to learn outside, one little girl wasn’t afraid to ask the big questions.

“Has the Queen ever had pizza?” 8-year-old Nadirah inquired, but Kate was stumped.

“You know, that’s such a good question. I don’t know,” the royal responded. “I don’t know. Maybe next time I see her, shall I ask?”

Kate Middleton More

Can’t get enough of PEOPLE’s Royals coverage? Sign up for our newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!

Kate Middleton More

Darren McGrady, who previously served as a personal chef to the 92-year-old monarch, told The Telegraph that she sticks to a strict diet and isn’t one to experiment with different flavors.

“Sadly, the Queen is not a foodie,” he said. “She eats to live, unlike Prince Philip who loves to eat and would stand and talk food all day.”

He added, “No starch is the rule. No potatoes, rice or pasta for dinner. Just usually something like grilled sole with vegetables and salad.”

RELATED: Kate Middleton Makes a Chilly Winter Visit — and a Bird Box! — During Community Garden Outing

Kate Middleton and Queen Elizabeth More

The Queen is also said to hate garlic, a fact that Camilla, Duchess of Cornwall recently revealed. During an appearance on MasterChef Australia, she said garlic is a “no-no” — especially at royal events and state banquets where there’s lots of chatting.