Two ingredients, tapioca starch and wheat starch, are found in Asian markets.
1½ cups regular rice flour
½ cup tapioca starch
5 tablespoons wheat starch
½ teaspoons salt
3 cups water
2 tablespoons vegetable oil, plus additional oil for pans
In a bowl, combine the rice flour, tapioca and wheat starches, salt, and water. Stir well with a wooden spoon until velvety. Strain through a sieve into a bowl. Add the tablespoons oil and mix well. Let rest for 3 minutes.
Oil 2 shallow pans each 8 or 9 inches square. Bring about ½ inch water to a boil in a steamer pan with the rack in place. Stir the dough. Pour about ½ cup into an oiled pan, just enough to coat the bottom. Place on the rack, cover the batter with a kitchen towel, and place the lid on the steamer. Steam for 5 minutes until set. Remove the pan from the steamer and place it in a larger pan with ½ inch cold water. When completely cool, loosen the noodle and transfer it to an oiled baking sheet. Lightly oil the top.
This sheet is complete. Repeat the process until all the batter is steamed. Then wrap tightly in plastic wrap and refrigerate for 2 hours before cutting. The sheet can be cut into any size noodles or any shape.
Remember that the noodles must be soaked before cooking. Very fine noodles need only to be doused in hot or boiling water.