Stir-Fried Morning Glory with Garlic and Fermented Bean

There is a version of this dish sold from woks all over Thailand where the cook lets the burner throw actual flames up the side of the pan, the vegetable catches a lick of fire, and the whole thing is done and plated before you’ve finished ordering. Pad pak bung fai daeng — stir-fried morning glory “with red fire” — is proof that the best vegetable cookery is sometimes the fastest. Morning glory is a hollow-stemmed green with crunchy stalks and tender leaves, and its whole charm depends on cooking it in ninety seconds over a ferocious heat so the stems stay crisp and squeaky while the leaves just collapse. Smashed garlic, fresh chilli and a spoonful of fermented soybean paste give it a savoury, salty, faintly funky backbone. It’s a two-minute side that tastes like a restaurant, and the only real skill is committing to the heat.

What morning glory is, and where the dish belongs

Morning glory goes by many names — water spinach, ong choy, kangkong, pak bung, rau muống — and it’s a semi-aquatic green grown across South and Southeast Asia, in India, China, Vietnam, the Philippines and Thailand. It grows fast in warm, wet ground and has been eaten for centuries as a cheap, abundant everyday vegetable. The plant has two useful parts: a hollow, crunchy stem and soft, arrow-shaped leaves, which cook at completely different speeds and are the reason the stir-fry needs a little sequencing.

The fiery Thai version, pad pak bung fai daeng, is the one most people meet first, a street-food and rice-shop staple built on garlic, chilli, oyster sauce and fermented soybean. But the same green turns up stir-fried with shrimp paste (belacan) in Malaysia and Singapore, with fermented bean curd in southern China, and simmered in the sour soups of Vietnam. What links them is the fermented ingredient — soybean paste, shrimp paste or bean curd — which supplies the deep, salty, umami-rich savour that a fast-cooked green can’t generate on its own. I use tao jiao, Thai yellow soybean paste, made from soybeans fermented with salt and koji; it’s milder and more accessible than shrimp paste, keeps for months in the fridge, and gives exactly the funk this needs without dominating.

Heat is the whole technique

The reason restaurant stir-fries taste the way they do is a Cantonese concept called wok hei, “the breath of the wok” — a faint, smoky, seared aroma that comes from cooking over an extremely high flame where droplets of oil and sauce vaporise and briefly ignite around the food. Domestic hobs can’t reach the ferocious output of a commercial wok burner, so you can’t fully replicate it, but you can get much closer than most home cooks do by respecting two rules. First, get the wok properly, frighteningly hot before any oil goes in — hot enough that it’s genuinely smoking, which for a green like this is the difference between searing and stewing. Second, keep everything moving and get it out of the pan the instant it’s done.

The enemy is water. Any liquid clinging to the vegetable, or crowded into a cool pan, drops the temperature and the food steams instead of searing, going limp and grey. This is why you shake the morning glory as dry as you can, why you don’t tip in more than the wok can handle at once, and why the sauce is mixed in advance and added in a single splash rather than dribbled in ingredient by ingredient — every second the pan spends below searing heat is a second the stems spend going soft. Adding the thicker stems twenty seconds ahead of the leaves gives them the head start they need, so the two parts of the plant finish at the same moment: stems still crunchy, leaves just wilted, everything vivid green.

Building the sauce and treating the garlic

Because the cooking is so fast, the sauce has to be ready before the wok is lit — there’s no time to measure once things are moving. Yellow soybean paste brings salt and ferment funk, oyster sauce adds a sweet-savoury depth and body, a little sugar rounds the salt, and a splash of water lets it all coat the greens rather than clinging in claggy lumps. The garlic is smashed rather than finely chopped on purpose: whole smashed cloves release their aroma into the oil without the small pieces that would burn to bitterness in a pan this hot. They go in for only a few seconds before the vegetable follows, just long enough to perfume the oil.

The recipe

Serves 2-3 as a side with rice.

Ingredients

• 1 large bunch morning glory (about 300g)
• 2 tbsp high-smoke-point neutral oil
• 4 garlic cloves, smashed
• 2 red bird’s eye chillies, sliced
• 1 tbsp yellow soybean paste (tao jiao)
• 1 tbsp oyster sauce (or mushroom sauce)
• 1 tsp light soy sauce
• 1 tsp sugar
• 2 tbsp water or light stock
• 1 tsp Shaoxing wine or dry sherry (optional)

Method

1. Wash the morning glory and shake it very dry. Cut into 6cm lengths, keeping thicker stems separate from the leaves.
2. Stir the soybean paste, oyster sauce, soy, sugar and water together in a bowl.
3. Heat a wok over the highest heat until smoking, then add the oil.
4. Add the garlic and chillies, stir 5-10 seconds until fragrant.
5. Add the stems, toss 20 seconds, then add the leaves and the wine down the side of the pan.
6. Pour in the sauce and stir-fry hard for 60-90 seconds, until stems are crisp-tender and leaves just wilted.
7. Tip onto a plate at once and serve with rice.

Tips, substitutions and storage

If you can’t find morning glory — look in Chinese, Thai and Vietnamese grocers, usually in big fresh bunches — this method works well with any sturdy leafy green that has a crunchy stem: choy sum, on choy’s cousins, or even a bunch of spinach with the thick stalks (though tender spinach needs even less time). For a vegetarian or vegan plate, swap the oyster sauce for a mushroom “oyster” sauce and check your soybean paste, and you lose nothing. If bird’s eye chillies are too fierce, a milder red chilli, deseeded, gives colour and warmth without the searing heat.

This is emphatically a cook-and-eat-now dish; it does not keep. The leaves weep and the stems go soft within an hour, so cook it last, once the rice and everything else is on the table. There’s nothing to store and nothing to make ahead beyond mixing the sauce.

Variations

For a version with more body, add a handful of small peeled prawns to the smoking oil just before the garlic, sear them for thirty seconds, then continue as written — they cook in the same ninety seconds. A teaspoon of shrimp paste stirred into the sauce takes it towards the Malaysian kangkong belacan style, funkier and deeper, if you like that intensity. Serve it as part of a fast vegetable spread alongside tenderstem with garlic, chilli and lemon and blistered green beans with garlic and almond, and you’ve got three crisp, garlicky greens on the table in under fifteen minutes between them.