Banh xeo, the crepe you are supposed to wrap

The name is the sound. Banh xeo means sizzling cake, from the noise the batter makes when it hits the oiled pan, and a kitchen that sells it can be found by ear before it can be found by sign.

What is in a banh xeo?

A banh xeo is a thin crepe of rice flour, coconut milk and turmeric, filled with pork belly, prawns and bean sprouts. The cook pours the batter into a very hot pan so the edges fry to a crisp lace while the centre stays soft.

Banh xeo batter carries no egg. The yellow is turmeric, which is the single most common misunderstanding about the dish and the reason western recipes keep adding eggs that do not belong.

Around the filling come the leaves: lettuce, mustard greens, mint, perilla, sometimes fig leaf or young mango. The herb guide covers the ones that turn up most often.

How are you supposed to eat it?

Tear a piece off, wrap it in a leaf with herbs, dip the parcel in the sauce and eat it in one. The crepe is not a plate of food to be cut up; it is a filling that arrives in a shell.

Use your hands. A pair of chopsticks helps to move a piece onto the leaf and does nothing after that, which is why nobody at the table is using them by the second mouthful.

Do it while the crepe is hot. The crisp edge lasts about five minutes, and a banh xeo eaten slowly turns into something soft and oily that nobody ordered.

Why does the sauce change from place to place?

The dipping sauce follows the region, and the crepe follows the sauce. In the south it is nuoc cham — fish sauce cut with water, sugar, lime and garlic — which is sweet and light against a big rich crepe.

Around Hue and Da Nang the same dish arrives with a thicker peanut and fermented soybean sauce, or with mam nem, a pungent anchovy paste. The fish sauce guide explains how far that family stretches.

Taste before you dunk. The central sauces are much stronger than the southern one, and a first parcel drowned in mam nem tastes of nothing else.

How big is a banh xeo?

Southern crepes run to about 30 cm across, and central ones to about 12 cm. That single difference changes the meal: one southern crepe is lunch, while a central order arrives as three or four small ones.

The south folds its crepe once, into a half moon, and serves it with a basket of leaves. Ho Chi Minh City kitchens do this on an industrial scale at lunchtime.

The small central version is closer to a snack and is often sold alongside banh khot, the little round cakes cooked in moulds. The pancake guide separates the three dishes that share the word.

What does one cost?

A crepe runs 30,000 to 60,000 dong at a street kitchen, which is one to two dollars at about 26,000 dong to the US dollar. A plate of small central ones costs about the same and feeds one person.

Sit-down restaurants charge two to three times that, and the crepe is usually made in advance and reheated, which defeats the entire point. The cheap eating guide covers how to read the difference.

Look for a kitchen where the pans are visible from the street. Three or four pans working at once is the sign of a place selling enough to keep the batter fresh.

When do kitchens sell it?

Banh xeo trades in the late afternoon and the evening, which makes it one of the few Vietnamese specialities that is not a breakfast dish. Pans go on around four and stay on until the batter runs out.

Some southern kitchens open at lunch as well. Anywhere selling it at nine in the morning is aiming at tourists, because the dish belongs to the end of the day rather than the start of it.

The evening hours make banh xeo a useful dinner when the rest of the street food guide points at morning — a point the breakfast guide makes about almost everything else.

Is there a version without pork or prawns?

Every kitchen can make banh xeo chay, the vegetarian version, and many sell it on the first and fifteenth of the lunar month when the chay trade picks up. Mushrooms, tofu and extra sprouts replace the meat.

The batter never contained anything animal, so the only thing to check is the dipping sauce. Ask for the soy version rather than nuoc cham, which is fish sauce by definition.

The vegetarian guide covers the word chay, which is the one word that does most of the work in this situation.

Where is it worth eating?

The Mekong Delta and Ho Chi Minh City make the largest and most generous versions, and Da Nang makes the best small ones. Both are worth a detour rather than a search for the single famous address.

Hue serves a close cousin under a different name, banh khoai, which is smaller, thicker and fried harder, and comes with the peanut and soybean sauce rather than nuoc cham. A visitor who orders banh xeo in Hue often gets that instead, and it is not a mistake.

The Mekong Delta versions are the ones with the extra filling: mung bean, sometimes duck, sometimes coconut in the batter. The city-by-city food guide says which dish belongs where.

How many should you order?

One southern crepe per person, or three to four of the small central ones. Kitchens sell them singly rather than as a set, so ordering is a count rather than a menu choice.

Add a plate of extra leaves if the basket runs out, which it will. Leaves are free or cost 10,000 dong, and running out of wrappers halfway through a 30 cm crepe is the usual first-timer problem.

Two people can share one southern crepe as a starter before something else. Nobody will comment, and most street kitchens sell one other dish alongside it for exactly that reason.