Har gow (虾饺) is considered the benchmark test of a dim sum chef's skill. A perfect har gow has a translucent, slightly chewy wrapper made from wheat starch and tapioca starch (not all-purpose flour), a crisp-tender skin that is neither gummy nor stiff, and a filling of plump whole shrimp with a clean, sweet flavour. The wrapper should be thin enough to reveal the pink of the shrimp beneath but sturdy enough to be picked up with chopsticks without breaking. The pleating — 7 to 13 pleats along one side — is the technical sign of a skilled dim sum hand.
The wheat starch dough: 150g wheat starch (澄面, cheng mian), 50g tapioca starch, 1/2 tsp salt, 200ml boiling water. Mix while water is still boiling hot — the starch gelatinizes immediately. Knead 5 minutes. Rest 10 minutes covered. The filling: 300g whole shrimp, peeled, deveined, and roughly chopped (not minced). Season with salt, sugar, white pepper, sesame oil, a pinch of cornstarch, and 1 tbsp diced bamboo shoots for crunch. Rest the filling 20 minutes. The wrapper: Roll or press (using a cleaver blade — the traditional method) a piece of dough to a very thin circle (2-3mm). The pleating: Place filling to one side. Bring the other side over to form a half-moon. Pleat the back of the wrapper — 7 to 9 pleats minimum. The front remains smooth.
Using regular flour: All-purpose flour produces an opaque, chewy skin completely unlike har gow. Only wheat starch produces the correct translucent, tender-but-firm texture. Mincing the shrimp: Har gow filling should have distinct pieces of shrimp.
Fuchsia Dunlop, Land of Fish and Rice (2016); Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009)