If you only eat it when you have a grandma that remembers how to make it, I would consider that the very definition of "traditional". And also interesting to hear about!

(But yea, perhaps not "everyone here eats" in that case. And yet, if everyone knew what it was -- even if it's "what grandma used to eat" -- I'd even let that slide. I don't eat what my grandparents ate, but I know more about it than a foreigner.)