Prep the aromatics and greens: thinly slice the Garlic and roughly chop the Thai bird's eye chilies to your preferred heat level. Wash the Water spinach (pak boong) and separate the thicker stems from the leafy tops so they cook evenly.
Make the sauce: in a small bowl whisk together the Oyster sauce, Thai fermented soybean paste (tao jiew), Fish sauce, Light soy sauce, Sugar and a splash of Water until smooth and slightly runny.
Heat your wok or a large skillet over high heat until very hot, then add the Neutral oil. Once shimmering, add the sliced garlic and chopped chilies and stir‑fry briefly until fragrant and just starting to color—be careful not to burn the garlic.
Add the thicker water spinach stems first and stir continuously for about 30–45 seconds so they begin to soften but remain crisp.
Toss in the leafy tops and pour the prepared sauce over the greens. Stir and toss quickly so the sauce coats everything and the leaves wilt but retain a bright color—this should take another 30–60 seconds.
Taste and adjust: if it needs more saltiness add a little more Fish sauce or soy, or a pinch more Sugar for balance. Serve immediately while hot as a side or over steamed rice.
