You know a Vietnamese restaurant is authentic when the waitress has to teach you how to eat your lunch.

When I ordered the daily special at Thuan Loi, Nicki, the youngest of eight in the Vietnamese family that owns the decade-old restaurant, recommended a fork rather than chopsticks. The crepe ($11.95) is "sort of like an omelet," she said. But when I started to eat it like one, she very politely rushed over, saying, "Could I show you how we eat it?"

Why not?

It quickly became clear I wouldn't be reading the book I'd brought along for this lunch on my own. Vietnamese crepe took two hands and twice that many napkins, but it was well worth it. It seems the crepe's crispy exterior is yellow not because of egg but from the turmeric-seasoned flour used to make it. Inside the thin folded pancake were tiny shrimp and bean sprouts. (It also comes with pork, but I went with all shellfish.) You cut a slice, wrap it in an iceberg lettuce leaf along with fresh mint and basil, and dip it in a clear, not at all fishy-tasting, fish sauce.

It was delicious. Fresh-on-the-stem herbs were such a treat that I used 90 percent of them and took a sprig with a leaf or two left on it to enjoy the heady aroma of fresh basil all day. The crepe was filling but refreshingly light.

The huge menu features dishes from China and Vietnam, including the latter's well-known noodle soup called pho. On the recommendation of a regular customer having an early lunch, I chose a Vietnamese hot and sour soup called canh chua (all the dishes are listed in English and Vietnamese; most of the family is bilingual) to bring home for dinner. I added shrimp (large in this) to the aromatic blend of "tomatoes, celeries, bean sprouts and other vegetables." This comes with a pint of nutty, slightly sticky rice.

Growing up and cooking in the United States, I tend to think of broth-based soups as a first, rather than main, course. So, the $14.95 price for a large portion seemed a little expensive.

But the light, fruity (there was some sort of citrus plus possibly Asian pear in it) soup was so delicately tasty that we considered driving back that very night to get more. The rice was a nice addition, making it more of a meal. Thuan Loi uses a 1 to 5 system of spiciness. We ordered 3 and could have gone to 3 1/2, but 5 would have been explosive.

I guess if the wonderful blend of flavors in this soup becomes an obsession, and it could, I'll have to visit the family's Vietnamese market in West Dennis and start experimenting with spices. And I'd best do it soon. Although the restaurant is open through the end of the year, the market will be closing before that.

Thuan Loi is easy to miss because it looks like a house and is modest to the point of shabby from the outside. But the inside is inviting enough and the air smells good enough to eat — the aromas are a harbinger of the made-to-order meals being prepared by the family matriarch. There are always family members working, and the father will share stories of his life in Vietnam.

Hours: 11:30 a.m. to 9 p.m. Tuesday through Sunday

Thuan Loi Restaurant

1300 Main St. (Route 28)

South Yarmouth

508-398-5592

By Gwenn Friss