Mustard

"All sliders are served with our special garnish. Sernpidalian mayo-ketchup and Bimm mustard available upon request."

- The Dex's Diner menu

Mustard was an edible item that was served in Dex's Diner as a side order with any sliders, before its destruction in 19 BBY. Varieties included Bimm mustard and Boontaspiced mustard.

Behind the scenes
Mustard is mentioned in the Star Wars Hyperspace exclusive Dining at Dex's, which represents the menu of Dex's Diner. In real life, mustard is a popular condiment made from the ground seeds of mustard plant.