Cockles are sometimes called blood clams because the liquid that the raw (or lightly blanched) bivalves release when opened is dark red. They look similar to clams, except that cockle shells have deep, narrow ridges that radiate out from the hinge.

These dishes couldn’t be easier to make, except for two drawbacks: it’s hard to find cockles in Hong Kong, and once you have them, they need to be cleaned very thoroughly. I see them fairly often in the seafood section of Tai Po Market, and you can try ordering them from shops that specialise in Thai ingredients, especially those in Kowloon City.

Chiu Chow-style marinated cockles

To clean cockles, start by giving them a good rinse in a colander. Keep them in the colander and prepare two bowls of water: one for washing the cockles, and a second one of salted water (75 grams of sea salt dissolved in 1½ litres of water) to put the scrubbed cockles into so that they can purge.

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Use a stiff toothbrush to clean the cockles, occasionally dipping them and the toothbrush into the first bowl of water to rinse away mud (change the water in this bowl whenever it becomes dirty). When each cockle is cleaned, place it into the bowl of salted water. Discard any cockles with broken shells.

Once all the cockles have been cleaned, leave them in the salted water for several hours, and they will spit out the mud in their shells. If the water becomes dirty, drain the cockles, rinse out the bowl, then add fresh water and salt in the same amounts as before.

Food book: recipes for your Chiu Chow street food favourites

When cooked briefly, cockles often remain tightly closed, unlike clams and mussels, which open when heated. These cockles are blanched for only 30 seconds, so they are still basically raw. They should not be eaten by the very young or the very old, or by anyone else with a compromised immune system. And as with all seafood, buy your cockles from a reputable supplier.

Susan Jung’s recipe for champong clams with black bean sauce

Don’t be surprised at the use of fish sauce in this recipe – it’s a common ingredi­ent in Chiu Chow cuisine. This sauce is also delicious poured over raw shrimp: cut each shrimp down its back and remove the vein, but keep the shells on. Marinate the shrimp for a couple of hours in the fridge.

750 grams cockles, cleaned
Salt, as needed
100ml Thai fish sauce
50ml sake
15 grams granulated sugar
4-5 large garlic cloves
6-8 red bird’s-eye chillies
A handful of fresh coriander leaves

In a medium-sized bowl, mix the fish sauce with the sake, then add the sugar and stir until dissolved. Chop the garlic and cut the chillies into thin rounds, squeezing out as many seeds as possible. Add the garlic and chillies to the fish sauce mixture.

Bring a large pot of salted water to the boil and add more salt until it tastes like seawater. Place the cleaned cockles in a colander, then carefully pour them into the boiling water. Leave for 30 seconds, then drain in a colander. Shake the colander to rid the cockles of as much water as possible, then put them – still hot – into the bowl containing the fish sauce and sake mixture. Mix thoroughly, then leave at room temper­ature until the cockles are barely warm (about 15 minutes).

Quick seafood recipe: fried stuffed clams

Roughly chop the coriander leaves and mix them in, then transfer all the ingredi­ents to a flat container with a lid. Refriger­ate for several hours, mixing the ingredi­ents often so they’re evenly marinated. Serve the cockles cold, and let your guests pry the shells open (it’s not easy).

Stir-fried cockles with holy basil

750 grams cockles
1 medium-sized shallot
2 garlic cloves
1-3 red bird’s-eye chillies
30ml Thai fish sauce, or to taste
1 tsp granulated sugar
A pinch of finely ground white pepper
15ml fresh lime juice, or to taste
A small handful of holy basil leaves
About 10ml cooking oil

Clean and purge the cockles as instructed in the first recipe, then drain in a colander. Thinly slice the shallot and garlic cloves. Cut the bird’s-eye chillies in half lengthwise and scrape out and discard the seeds. Chop the chillies about 3mm thick. Add the sugar to the fish sauce and stir to dissolve, then mix in the white pepper and about 20ml of cool water.

Susan Jung’s three favourite clam recipes

Place a wok over a high flame and when it’s hot, add the cooking oil. When the oil is hot, add the shallot, garlic and chillies and stir briefly, then mix in the cockles. Stir in the fish sauce/sugar mixture, then reduce the heat, cover the wok with the lid and simmer for several minutes. Mix in the lime juice then taste the liquid; adjust the seasonings if needed. Stir in the holy basil leaves and serve immediately.