The Thai Wok: How to Stir-Fry, with Pad Kra Pao as the Example

Walk past a Thai street kitchen at lunchtime and the first thing you notice is the noise: a roaring gas burner, a metal ladle scraping round a wok, and the hiss of sauce hitting hot metal. A plate of stir-fried rice or meat appears in a couple of minutes. It looks effortless, but it relies on a few clear habits that any home cook can learn.

Stir-frying came to Thailand largely through Chinese cooking, and the wok, known in Thai as krata, is now part of almost every kitchen in the country. Many of the most common one-plate meals, from pad see ew to fried rice and pad kra pao, are cooked in one.

Why the wok

A wok's round shape puts a small, very hot area at the bottom, where the flame hits, and cooler sloping sides. Food can be seared in the centre and pushed up the sides to rest, and its depth makes tossing easy without throwing food onto the stove. A thin carbon steel wok heats up quickly and responds fast when the heat is turned down. It needs seasoning with oil before first use and should be dried over heat after washing to stop it rusting. Over time it builds up a dark, slick surface that food does not stick to.

Heat and preparation

Stir-frying is fast, which means there is no time to chop or measure once the wok is hot. Everything should be ready before the burner goes on.

• Cut ingredients into similar, small sizes so they cook at the same rate.
• Pat meat and vegetables dry. Wet food steams instead of searing.
• Mix the sauces in a small bowl beforehand, so they go in together in one pour.
• Have the plate and the rice ready, as stir-fries are best eaten straight from the wok.
• Use an oil with a high smoke point, such as vegetable, rapeseed or peanut oil.

Heat the empty wok until it just begins to smoke, then add the oil and swirl it round. Food added to a properly hot wok sizzles loudly and sears at once. If it goes in quietly, the wok was not hot enough.

The order of things

Most Thai stir-fries follow the same sequence. Aromatics go in first, then the main ingredient, then the sauce, then anything delicate at the very end.

Garlic and chilli usually lead. They are often pounded together roughly in a mortar rather than chopped, which releases more of their juice and flavour. They need only a few seconds in hot oil, just long enough to smell fragrant and start to colour. Burnt garlic is bitter, so be ready to add the next ingredient quickly. Frying chillies in a hot wok also releases fumes that make everyone in the kitchen cough. A working extractor or an open window helps.

Meat goes in next, spread out so it can sear. Hard vegetables such as long beans or carrots follow, then softer ones. The sauces go in once the main ingredients are almost cooked, often with a splash of water or stock to bring everything together. Herbs and leaves such as basil go in last, sometimes off the heat, so they wilt without turning black.

Small batches

The most common reason home stir-fries turn out soggy is overcrowding. Too much food at once drops the temperature of the wok, and the ingredients release their liquid and stew instead of frying. Street cooks almost always cook one or two portions at a time for this reason. At home, cook a single portion if possible, or sear the meat in batches, set it aside, and bring everything back together for the sauce at the end.

Pad kra pao, step by step

Pad kra pao is stir-fried meat with holy basil, and it may be the most commonly ordered lunch in Thailand. It is usually made with minced pork or chicken, served over jasmine rice and topped with a fried egg with crisp, lacy edges (khai dao). It is also an ideal dish for learning wok technique, because it uses every step above in about three minutes.

Holy basil (kra pao) is the essential ingredient. It has a peppery, clove-like flavour quite different from Thai sweet basil (horapha), which is more like aniseed. Sweet basil makes a pleasant dish but not a true kra pao. Some cooks add long beans or onion, others insist the dish should be only meat and basil. Both versions are common.

1. Pound 3-4 cloves of garlic with a few bird's eye chillies into a rough paste.
2. Mix the sauce: oyster sauce, light soy sauce, a few drops of dark soy for colour, a little fish sauce and a pinch of sugar.
3. Heat the wok until smoking, add oil, then the garlic and chilli. Stir for a few seconds until fragrant.
4. Add the minced meat, break it up with the ladle and let it sear before stirring.
5. When the meat is nearly cooked, pour in the sauce and a splash of water, and toss until glossy.
6. Turn off the heat, add a large handful of holy basil leaves, and toss until just wilted.
7. Serve at once over rice, with a fried egg on top and a small dish of fish sauce with sliced chillies on the side.

The fried egg is cooked Thai style, in a generous amount of very hot oil, spooning oil over the top so the white puffs and crisps at the edges while the yolk stays runny.

Wok hei and the home stove

Wok hei is a Cantonese term, often translated as the breath of the wok. It describes the smoky, slightly charred flavour that comes from cooking over very high heat, where oil and sauce touching the hot metal briefly scorch and sometimes catch fire. Thai street cooks working over powerful gas burners get it in many of their dishes. One famous example is pak boong fai daeng, morning glory stir-fried over a flame so high it sends fire up the side of the wok.

Domestic hobs rarely produce that much heat, but there are ways to get closer:

• Use the largest burner and give the wok several minutes to heat through.
• On an electric or induction hob, a flat-bottomed wok or a heavy cast iron frying pan makes better contact with the heat than a round wok.
• Cook smaller quantities than feels natural.
• Toss less often. Letting food sit for a few seconds between stirs allows it to sear and colour.

A home stir-fry may not taste exactly like one from a street cart, but with a hot pan, ingredients ready and food cooked in small amounts, it can come surprisingly close.