Feng zhua (凤爪, phoenix claws — the poetic Cantonese name for chicken feet) are one of the most time-consuming dim sum preparations and one of the most satisfying in textural complexity — the chicken feet are deep-fried until the skin puffs and blisters, then soaked in water to soften, then braised in a black bean and oyster sauce braise until the skin is pillowy-soft, gelatinous, and deeply seasoned. The collagen in the chicken feet dissolves partially during the long braising to produce the characteristic sticky, gelatinous quality — each foot clings slightly to the lips when eaten. The bones provide structure; the goal is to eat all the skin and soft tissue around each small joint while leaving the bones clean.
Step 1 — Deep-frying: Clean chicken feet, pat completely dry. Deep-fry at 180C for 5-8 minutes until the skin is golden and puffed in patches. Remove and immediately plunge into cold water. Soak 30 minutes to 2 hours — the soaking softens the puffed skin and allows it to become deeply wrinkled and porous, which will absorb the braising sauce better. Step 2 — The braise: Drain and dry the soaked chicken feet. In a wok or braising pot, fry black bean sauce (douchi + garlic), fresh chillis, and ginger. Add the chicken feet. Add oyster sauce (2 tbsp), light soy (1 tbsp), dark soy (1 tsp), sugar (1 tsp), Shaoxing wine (2 tbsp), and enough chicken stock to partially submerge. Braise over medium-low heat for 45-60 minutes until the skin is completely tender. Step 3 — Dim sum service: Arrange in bamboo steamers. Steam 10-15 minutes before serving to reheat and ensure the gelatinous sauce clings to each foot.
Skipping the deep-fry step: Without the pre-frying, the chicken feet skin does not develop the porous, puffed quality that absorbs the braising sauce. Insufficient soaking after the fry: Brief soaking produces a tough outer skin. Minimum 30 minutes in cold water.
Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009)