Gravy??

Where I work if someone is running an easy job the people there say “You’re running gravy tonight.” This has always been a bizarre term to me. Most of the rest of the english speaking world say “Cake” as in: “That job is a piece of cake.” But not here in good ol’ Oklahoma. They gotta confuse everything. I told my wife about this phrase and she said, “That’s weird because gravy isn’t that easy to make.” So why gravy? Personally I like cake more than I like gravy, actually I hate gravy, but even if I liked it I think I’d like cake more. Why do I spend time trying to dissect the intracacies of the Okie mind? I just don’t know.