Glass noodles (wun sen — mung bean starch noodles) stir-fried in a wok with egg, pork or chicken, tomatoes, spring onion, and celery — seasoned with oyster sauce, fish sauce, and white pepper. Pad woon sen is a soft-textured stir-fry — the glass noodles absorb all the sauce and cooking liquid in the wok, becoming translucent, slightly sticky, and deeply flavoured throughout. It is less aggressive in heat and flavour profile than pad Thai and pad see ew (Entries TH-11, TH-39) — a gentler preparation suited to the mild-flavoured glass noodle's character.
**Glass noodle preparation:** - Dried wun sen must be soaked in cold water for 15–20 minutes until fully softened. They should be pliable and translucent before entering the wok. - Unlike rice noodles, over-soaked glass noodles do not clump in the wok — they can be soaked for up to 30 minutes without textural damage. - Glass noodles are extremely absorbent — they drink the sauce in the wok and swell. Add slightly more sauce liquid than seems needed; the noodles will absorb it rapidly. **The preparation:** 1. Wok at high (not maximum) heat — glass noodles scorch more rapidly than rice noodles. 2. Oil, garlic. 15 seconds. 3. Protein. Stir-fry briefly. 4. Add tomatoes (quartered) and celery (sliced on the bias). 1 minute. 5. Add the drained glass noodles. Add oyster sauce, fish sauce, a small amount of water. 6. Toss and stir until all liquid is absorbed by the noodles — 2–3 minutes. 7. Add egg: create a space in the wok, scramble the egg briefly, fold into the noodles. 8. Spring onion and white pepper. Serve. Decisive moment: The moment all the sauce liquid has been absorbed by the glass noodles — the wok appears dry, the noodles are glossy and translucent rather than white-opaque. This is service time: continued heat after the liquid is absorbed scorches the noodles rapidly.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)