New Delhi, May 9 -- Any country that has a department of public service for eating deserves a visit. I discovered this only during our nine-day tour of Vietnam last month, confirming that beyond the disquieting reality that it is a totalitarian state, it takes food very seriously indeed.

But street and restaurant food can reveal only so much about a cuisine and its people.

So, on our last day in Hanoi, I signed up for a cooking class in Alex Nguyen's modest home, somewhere beyond the tourist traps. With two other pupils-American nurses from near Edison, the desi side of New Jersey-Alex first took us through a local market to buy ingredients. There was not a tourist in sight as we met her local pork merchant, an unsmiling older woman; he...