Bai zhuo (白灼, literally white scalding) is the Cantonese technique of briefly poaching food — typically vegetables and seafood — in light aromatic broth or salted water, then finishing with a drizzle of hot soy sauce and sizzling oil. The technique exemplifies Cantonese cooking philosophy: ingredients of impeccable freshness, handled minimally, dressed simply so that the ingredient's natural flavour is the point. Bai zhuo Chinese greens — morning glory, choy sum, or gai lan in a pool of oyster sauce and hot oil — is one of the most ordered dishes in any Cantonese restaurant.
The white-scalding sequence: 1. Bring a large volume of water to a rapid boil. Salt lightly and add a small amount of oil (prevents greens from discolouring). 2. Add greens or seafood. For gai lan or choy sum: 1-2 minutes. For shrimp: 2-3 minutes. For squid: 60 seconds. 3. Remove immediately when just cooked — greens should be vivid green and slightly resistant to the bite. 4. Pour Lee Kum Kee oyster sauce or light soy sauce over. 5. Heat 2 tbsp of oil until just smoking — pour over the dressed greens. The oil sizzles on contact, creating an aromatic bloom (lin you 淋油).
Adding 1 tbsp of neutral oil to blanching water prevents discolouration. Gai lan benefits from a 30-second rest off-heat before plating — residual heat continues cooking without overdoing it.
Overcooking greens: 1 minute too long = grey, limp vegetables. Insufficient water volume: Small pot of water drops below boiling when greens overwhelm it, producing steamed rather than blanched result.
Fuchsia Dunlop, Land of Fish and Rice (2016); Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009)