"If you must know, it was the crepes. Can't get decent ones anywhere but Paris. And the brioche." - Aziraphale
We don't often see Crowley eat in the television series, but I'm sure he'd make an exception if his crepes were doused in chocolate and alcohol. Aziraphale has an appreciation for tradition, and thus would appreciate the traditional buckwheat and savoury approach (and perhaps take a spoonful of Crowley's crème a la Chantilly...AKA whipped cream).
All of these ingredients were possibly found in revolutionary France, although they were moreso enjoyed by the wealthy. (I assumed they went all out after escaping from jail. Wouldn't you?)
♦︎ Good Omens ♦︎