Thinking about the banh mi. It's interesting to think about the history that landed this sandwich in Allston MA. France colonized Vietnam in the mid-nineteenth century, and that colonization lead to my sandwich. During the French colonization the Vietnamese embraced (or maybe more accurately were forced to adapt to) parts of French cuisine. Most deliciously baguette's which they now make with a combination of rice flour and wheat, and pate's. The banh mi is a direct result of the French colonial occupation of Vietnam, not to mention the complicated path this sandwich took the US.
The paths that foods take (immigration, colonization etc) to get to their current whereabouts say things not only about their origins, but also about their authenticity. Is a banh mi sandwich eaten in Massachusetts less authentic then a banh mi eaten in Hanoi?
Another example, my Grannie makes an apple pie with nutmeg and teaches the recipe to my Mum. Mum who favors cinnamon replaces the nutmeg and then teaches the pie to me. I prefer a lard crust to a butter crust so I change the piecrust. Is this still my Grannies pie?