We have a lot of meals here where we aren't sure HOW to eat it (Do I eat the head? How do you get the bones out of this?), and the wait staff has to jump in to mime it for us or even do it for us. When this dish arrived, we started faking our way through it, and since none of the five wait staff standing in a rank next to our table and watching us eat said anything, we figured we were doing alright.
This is ban xeo, which is often described as a Vietnamese pancake and is really more like a crepe. It's a thin batter that's folded over with whatever ingredients you've ordered. Mine is mushrooms and cuttlefish, and Ilene's is bean sprouts and cuttlefish.
We've had ban xeo before at a friend's house in Connecticut, but in that case we were shown how to roll up a small portion of the crepe inside a thin rice wrapper. You add in the other ingredients, like pieces of mint and basil, and then dip it in the fish sauce. We were expecting the same routine when we ordered ban xeo for the first time here, but no wrappers came with it. So we just started wrapping it in the large lettuce leaves.
We found out later when we observed friends eating this dish that we guessed exactly right, except that our technique is weak. It turns out that in the center of the country the rice wrapper method is common, and in the south the lettuce leaf method is common. They didn't say anything about how they eat it in the north.
-Robert