No dish is an island (even - especially - those dishes associated with islands, where traders historically dropped off all manner of staples and spices.) There are multiple cultures intertwined in everything we eat, although the ingredients may have collided so long ago that memories of the culinary collaboration are permanently lost in a haze of curry and tomato sauce.
That's not the case with Viet-Cajun crawfish, a dish with such a transparent evolution that sucking on a boiled mudbug is like chewing on a travel itinerary. Crawfish aren't especially popular in Vietnam, but when refugees from the war-torn country resettled on the U.S. Gulf Coast, they quickly took to the critters; cookbook author Andrea Nguyen told John T. Edge that "Vietnamese people like to pick at their food, to peel and eat with their fingers."
The fishermen soon developed crawfish rituals that incorporated elements of their native cuisine and the region's seafood traditions: The crawfish were boiled with Creole seasonings, in much the way that previous generations of southern Louisianans had pioneered, but then tossed in plastic bags with garlicky margarine and spritzed with lime - a purely Vietnamese invention.
And when the immigrants' children moved away, or their relatives arrived from Vietnam to make homes far from the Gulf Coast, the Viet-Cajun crawfish craze followed them. Around Seattle, there are now at least half a dozen crawfish houses. But the leader of the pack is The Cajun Crawfish, which distinguishes itself with fresh, fat crawfish and extraordinarily good bread (a Vietnamese carryover that isn't offered in every Viet-Cajun shack.)
While the "crazy hot" heat level is pretty tame - it takes a healthy kick to compete with all that butter - the messy Cajun seasoning is terrific. Be sure to dredge that soft, crusty baguette through it, perhaps while contemplating the gnarled family trees that reliably produce deliciousness.