Wu gok (芋角) is one of the most technically demanding and visually spectacular dim sum preparations — a deep-fried taro paste shell containing a filling of pork, shrimp, and mushrooms, the exterior forming a delicate, lacy honeycomb (網紗, wang sha) of thin, crisp taro tendrils as it fries. The honeycomb effect is the result of the taro paste expanding during deep-frying as steam from the filling pushes through the shell, creating a network of fine, crispy projections. A wu gok without the honeycomb is considered a failure — it means either the taro paste was wrong (too little fat, incorrect water content) or the frying temperature was wrong.
The taro paste: 400g taro (the starchy variety — Cantonese cooking uses the large, dry-fleshed taro called wu tou, 芋頭), peeled, cubed, and steamed until completely soft. Mash immediately while still very hot. Add: 50g wheat starch (澄面) dissolved in 50ml boiling water — mix immediately to cook the starch. Add: 60g lard (the fat is critical — lard produces the honeycomb effect; vegetable oil does not). Add: 1 tsp sugar, 1 tsp salt, a pinch of five spice. Mix vigorously until smooth. Cool to room temperature. The filling: 100g minced pork, 50g diced shrimp, 30g diced reconstituted dried shiitake mushroom. Season with oyster sauce, soy, sesame oil. Stir-fry briefly until 80% cooked. Cool. Shaping: Take a golf-ball-sized piece of taro paste. Flatten into a disc. Place a small amount of filling in the center. Gather the taro paste around the filling to form an oval shape. Press firmly to seal. Frying: 160-170C — this temperature range is critical for the honeycomb. Too hot and the shell fries too quickly before the steam can create the lacy structure; too cool and the shell absorbs oil without forming the honeycomb. Fry 4-5 minutes, turning gently.
Insufficient lard in the taro paste: This is the most critical error. Without the fat component, the taro paste lacks the internal structure that allows the honeycomb to form. Frying at the wrong temperature: Both too hot and too cool produce a failure — too hot collapses the shell, too cool produces an oily result without the honeycomb.
Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009)