Blanch the soybean sprouts in boiling water for a few minutes until cooked, then drain.
Mix together the flour and just enough water to make a firm dough. Knead until smooth and elastic. Cover with cling film and let rest for at least 2 hours.
Transfer the dough into a large bowl and enough cold water to cover the dough. Knead the dough under the water for about 10 minutes or until the water clouds.
At this time, some of the starch will have dissolved in the water and the dough will be very sticky. This is the first stage of the gluten dough formation.
Transfer the dough into another big bowl with clear water. Reserve the starchy water.
Continue to knead the dough under the water until it becomes cloudy again. Pour all of the cloudy water into the first bowl.
Repeat the process until the water is clear or until the water no longer clouds. You are then left with a gluten dough.
Put the gluten dough into a heat-proof dish and steam for 30 minutes. Remove and cool. Cut into diamond-shaped thin slices and set aside.
Put the starchy water into a bowl and refrigerate for 3 hours or until the water and starch separates. Carefully scoop out of the water and discard. Reserve the starch and stir into a paste.
Grease a large plate and pour a large spoonful of the starch paste and spread to form a thin layer. Steam for 2 minutes.
Remove the plate and submerge in cold water for 15 seconds. Take the dish out of the water and peel off the starch sheet.
Repeat until you use up all of the starch paste. Brush each starch sheet with oil to stop them from sticking together. Stack.
Rinse a knife and cut the cold starch sheets into narrow sheets. Mix the gluten pieces, starch strips, soybean sprouts, cucumber, salt, vinegar, hot chilli oil and sugar in a bowl. Toss well and serve.
Soybean sprouts can be purchased in Chinese/Oriental speciality shops. If unavailable, use beansprouts instead.
Oh wow. I remember many years ago, cookery school experiments where we had to make balls of dough, knead them and rinse in water until we were left just with balls of gluten. Just to show the difference between hard and soft flours. Thanks for reminding me :D - 27 Feb 2016