Osso Buco
See, I've got X again!
A drink for a change
Xocolatl
(In Mexican pre-Hispanic traditions, the Aztecs prized cacao beans and used them as currency as well as food for the upper classmen. They transformed cacao into a beverage called Xocolatl, which later came to be known as "chocolate.")
Source https://www.livestrong.com/article/268995-list-of-foods-that-start-with-x/