Nobody warns you that the sweet potato has to be cut by hand.

I learned it the wrong way, standing over a box grater, producing a soggy orange pad that fried into something closer to a hash brown than a fritter.

The real thing is lacy.

Thin matchsticks tangle into an open nest, the batter barely holds them together, and the oil gets into every gap so the whole disc goes shatteringly crisp.

A whole shrimp sits right on top, shell and all, curled and orange.

They sell these along the edge of Ho Tay, West Lake, in Hanoi, straight out of the fryer into a paper cone.

You tear off a piece, wrap it in a lettuce leaf with mint and rau ram, and drop the whole bundle into nuoc cham.

The lettuce is not a garnish. It's how the dish is eaten.

Cutting a pound and a half of sweet potato into matchsticks takes fifteen focused minutes, then you're at a pot of oil for another twenty.

My wife hovers near the kitchen around fritter number three, because the first two never make it to the table.

Crisp on the outside, sweet and soft where the potato is thickest, salty shrimp on top, and a dipping sauce that ties it all together.

I promise the matchsticks are worth it.

Table of Contents

What Is Banh Tom Chien Khoai Lang?

The name tells you exactly what it is, once you break it apart. Vietnamese dish names tend to be beautifully literal.

Banh tom means shrimp cake. Chien means fried. Khoai lang means sweet potato.

So: fried shrimp and sweet potato cake.

The dish is northern Vietnamese and it's tied specifically to Ho Tay, West Lake in Hanoi, where a strip of restaurants and stalls has been selling it for decades.

Shrimp are pulled from the lake, sat on a raft of sweet potato matchsticks, dipped in a turmeric batter, and deep fried into a flat golden disc.

The shrimp go on whole, shell on, heads sometimes still attached.

The shell fries to a crisp you eat right along with everything else, and it carries a lot of the flavor.

It arrives with a plate of lettuce and soft herbs and a bowl of nuoc cham, the sweet, sour, salty fish sauce dip that shows up alongside half of Vietnamese cooking.

Sound like a lot of components? It comes together faster than it reads.

Ingredients You'll Need

Three groups: the batter, the shrimp and sweet potato, and the table. Nothing here is exotic beyond a bottle of fish sauce.

For the Batter

All-purpose flour (¾ cup). The structure. On its own it fries a little bready, which is why it doesn't work alone.
Rice flour (½ cup). This is the crispness. Rice flour fries dry and brittle instead of soft. Don't skip it, and don't confuse it with glutinous rice flour, which is a different product entirely.
Cornstarch (¼ cup). Extra shatter, and it keeps the batter from getting gluey.
Turmeric powder (1 teaspoon). The signature yellow. It adds a faint earthiness but it's mostly there for color, and the color matters.
Baking powder (1 teaspoon). A little lift so the batter stays open rather than dense.
Egg (1 large). Binds and browns.
Cold sparkling water or club soda (1 ¼ cups). COLD is the operative word. Cold carbonated liquid keeps gluten lazy and puts bubbles into the batter. Plain cold water works, it's just a step down.
Salt (1 teaspoon) and black pepper (½ teaspoon). Season the batter properly. Under-salted fritters taste like nothing.

For the Shrimp and Sweet Potato

Whole shrimp, shell on (1 pound, small or medium). Heads off, shells left on, deveined through the back. Small shrimp fry through in the same time the batter takes. Peeled shrimp are fine, see the substitutions.
Fish sauce (1 tablespoon). Buy a real one. Red Boat, Three Crabs, Squid brand. It seasons the shrimp in about ten minutes.
Shallot (1, minced) and garlic (2 cloves, minced). Into the shrimp marinade.
Sweet potato (1 ¼ pounds). Peeled and cut into matchsticks 3 inches long and ¼ inch thick. Any orange sweet potato works. This is the part that takes time.
Neutral oil for deep frying. Enough for 2 inches of depth.

For the Table

Lettuce. Butter lettuce or green leaf. Soft leaves that fold without cracking.
Herbs. Mint, perilla (tia to), and rau ram if your market carries them. Cilantro is a reasonable stand-in.
Nuoc cham. Fish sauce, sugar, warm water, lime, garlic, chile. Two minutes to mix.

Equipment

A deep pot or wok. Something with tall sides. Fritters splash.
A shallow ladle or a small flat bowl. You build the fritter inside it and slide it into the oil as one piece. This is the single most useful trick in the recipe.
A thermometer. Oil temperature is the difference between crisp and greasy.
A wire rack. Drain on the rack, never on paper towels, which steam the underside soft.

How to Make Banh Tom

The order matters: batter first so it can rest, then the prep, then fry. Once you start frying you won't want to leave the pot.

Make the Batter

Whisk the flour, rice flour, cornstarch, turmeric, baking powder, salt, and pepper in a large bowl.

Beat in the egg, then pour in the cold sparkling water and whisk just until it comes together.

A few lumps are fine. Overworking it makes the fritters tough.

The consistency should be like thin pancake batter, loose enough to run off a spoon in a ribbon.

Let it sit in the fridge for 15 minutes while you do everything else.

Prep the Sweet Potato and Season the Shrimp

Peel the sweet potato and slice it into ¼ inch planks, stack the planks, and cut them into ¼ inch matchsticks about 3 inches long.

Use a mandoline with a julienne blade if you own one. A knife works and takes fifteen minutes.

Do NOT grate them. Grated sweet potato packs into a dense wet pad and fries greasy.

Drop the matchsticks into cold water as you go so they don't discolor, then drain and dry them thoroughly on a towel right before frying.

Toss the shrimp with the fish sauce, shallot, garlic, and a pinch of pepper. Let them sit 10 minutes.

Shape and Fry

Heat the oil to 350°F.

Toss a large handful of dried matchsticks with just enough batter to coat, maybe 3 tablespoons. You want them barely glued, not swimming.

Pile that into a shallow ladle, flatten it into a rough disc about 4 inches across, and lay one or two shrimp on top.

Lower the ladle into the oil and hold it for 10 seconds, then tip gently. The fritter releases in one piece.

Fry 4 to 5 minutes, flipping once at the halfway point, until deep golden and audibly crisp when you tap it.

Lift onto the wire rack. Fry 2 fritters at a time, no more, and let the oil climb back to temperature between batches.

How to Serve It the Vietnamese Way

Put the fritters in the middle of the table and let people build their own. Eating with your hands is the correct way, not a shortcut.

Break off a piece of fritter, roughly a quarter, with a bit of shrimp on it.

Lay it on a lettuce leaf, add a mint leaf and a piece of perilla, and roll or fold the leaf around it.

Dunk the whole bundle in nuoc cham and eat it in one go.

The lettuce and herbs cut the fried richness, the sauce brings sour and salt, and the sweet potato brings the sweetness. That balance is the point of the dish.

Nuoc cham, in two minutes: stir 3 tablespoons sugar into ¼ cup warm water until it dissolves. Add 3 tablespoons fish sauce, 2 tablespoons lime juice, 1 minced garlic clove, and 1 sliced red chile. Taste it. It should be sweet first, then sour, then salty. Thin with a little more water if it's aggressive.

Some Hanoi stalls float a few shreds of pickled green papaya and carrot in the sauce. Worth doing if you have twenty extra minutes.

Substitutions and Swaps

Peeled shrimp instead of shell on. Perfectly acceptable and easier for guests who won't expect to eat a shell. You lose some crunch and some flavor. Keep the tails on for looks.
Plain cold water for sparkling. Works. The fritter is slightly denser. Ice cubes in the water help.
Cornstarch for rice flour. Use ½ cup cornstarch in place of the rice flour if you can't find it. Not identical, still crisp.
Potato starch for everything. Some cooks use straight potato starch for an ultra light, almost glassy shell. Try it once you've made the standard version.
No perilla or rau ram. Mint and cilantro alone are fine. Don't skip the herbs entirely, the dish flattens without them.
Air fryer. Honestly, no. See the FAQ.

Expert Tips for Crisp Fritters

Dry matchsticks, always. Water on the sweet potato drops the oil temperature and turns the fritter greasy. Towel them properly.
Use less batter than feels right. The batter is glue, not coating. If you can see a pool of it in the ladle, you've used too much.
Hold the oil at 350°F. Below 325°F the fritter drinks oil. Above 375°F the outside darkens before the sweet potato softens.
Two at a time, no crowding. Each fritter drops the oil temperature by ten degrees or more.
Rack, not paper. Paper towels trap steam and the bottom goes limp within a minute.
Salt them the second they come out. A tiny pinch while the surface is still hot.

Make Ahead and Storage

The double fry. For a party, fry the fritters at 325°F for 3 minutes until pale and set, then hold them on a rack for up to 3 hours. Just before serving, fry again at 375°F for 2 minutes until deep gold. They come out crisper than a single fry.
Batter. Mix up to 4 hours ahead and keep it cold. Whisk briefly before using.
Nuoc cham. Keeps 2 weeks in the fridge and improves after a day.
Leftovers. Refrigerate up to 2 days. Reheat on a rack in a 400°F oven for 6 to 8 minutes, or in an air fryer at 375°F for 4 minutes.
NEVER the microwave. It turns a crisp fritter into a wet sponge in forty seconds.

Frequently Asked Questions

What is banh tom chien khoai lang, and where in Vietnam is it from?

It's a deep fried fritter of whole shrimp on a nest of sweet potato matchsticks in a turmeric batter. It comes from northern Vietnam and is most associated with Ho Tay, West Lake in Hanoi, where stalls and restaurants along the water have sold it for generations. It's eaten as a snack or an appetizer, wrapped in lettuce with herbs and dipped in nuoc cham.

Do you eat the shrimp shells?

In the traditional version, yes. Small shrimp fried shell on come out with a thin crisp shell that you eat along with everything else, and it adds real flavor. If that's not for you, peel the shrimp first and leave the tails on. Nobody will complain.

Can I use regular orange sweet potato, or does it have to be a Vietnamese variety?

Regular orange sweet potato is completely fine and it's what most home cooks use. Vietnamese and Japanese varieties are drier and slightly less sweet, so they fry a touch crisper, but the difference is small next to the difference matchsticks versus grating makes.

Why did my fritters come out greasy instead of crisp?

Three usual causes. The oil was under 350°F, the sweet potato was wet, or you used too much batter. Fix the temperature first, dry the matchsticks second, and cut the batter back until the sticks are barely glued together.

Can I make banh tom in an air fryer?

Not well. The wet batter runs through the basket before it sets, and the lacy structure depends on hot oil surrounding it from every direction. An air fryer is excellent for reheating already fried banh tom, at 375°F for about 4 minutes.

What is nuoc cham, and can I buy it instead of making it?

Nuoc cham is a diluted fish sauce dip balanced with sugar, lime, garlic, and chile. Bottled versions exist and they're usable in a pinch, but they run sweet and flat. Mixing it takes two minutes and five ingredients you already bought for this recipe.

How do I keep the fritters crisp for a party?

Use the double fry method. First fry at 325°F for 3 minutes, hold at room temperature on a rack for up to three hours, then finish at 375°F for 2 minutes right before serving. Holding fried fritters in a warm oven for more than about fifteen minutes softens them.

Do shrimp and sweet potato really go together?

They do, and this dish is the proof. The sweet potato is mild and sweet, the shrimp is briny and salty, and the fish sauce dip pushes both further in their own directions. It's the same logic behind shrimp with grits or shrimp with corn.

This is a weekend project, not a Tuesday, and I'm not going to pretend otherwise.

But the first bite of a hot fritter inside a cool lettuce leaf, dripping nuoc cham, is worth every minute at the cutting board.

Give it a try!

Recipe

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Banh Tom Chien Khoai Lang (Vietnamese Shrimp and Sweet Potato Fritters)

Prep Time 30

Cook Time 25

Total Time 55

Servings servings