Megan Markle might just be the healthiest royal. The meditation– and smoothie-lovin’ Duchess of Sussex has always prioritized clean cooking and filling her fridge with fresh fruit and veggies to use in homemade meals. But when it comes to her go-to pasta dish, tomatoes surprisingly take the back seat: Markle’s favorite sauce is all about a different vitamin-packed superfood.

Markle is essentially a pasta fanatic, given that Delish reports she seeks out new iterations of the carb-heavy dish whenever she’s traveling. And when she’s at home, her devotion remains the same—but with a healthy twist. She’s revealed in the past that her favorite recipe for sauce involves just three easy-to-find (and super-affordable!) ingredients: zucchini, water, and a some bouillon. “The sauce gets so creamy you’d swear there’s tons of butter and oil in it,” she says .

“The sauce gets so creamy you’d swear there’s tons of butter and oil in it.” —Meghan Markle

Evidently, a friend let Markle in on the hack to create the perfectly creamy sauce, which involves slow-cooking the zucchini for four to five hours—something she says perfectly breaks it down into a “filthy, sexy mush.” Then once it’s ready, all you have to do is toss it with your favorite pasta.

Now, there’s no word yet on whether the Queen or Prince Harry are fans, but this summer-squash-based dish is definitely worthy of being served in Buckingham Palace’s eco-friendly dining room.

This is Meghan Markle’s beloved smoothie recipe—and it sounds delicious. Or, find out her trick to staying bloat-free on flights.