Sieve the flour once, dissolve the salt in water and stir well.
Pour the starch and flour into a container, add 2/3 salt water, and grab the flour into a floccule.
Pour the remaining 1/3 salt water, continue to knead the dough and knead it into a ball as much as possible. Depending on the composition of flour, a proper amount of water may be needed. Generally speaking, the dough needs to be harder and rougher, but it's okay.
Prepare a dense bag and a large rolling pin (the longer the bending moment, the more labor-saving), put the coarse dough into the dense bag, hold both ends of the rolling pin with both hands, and press the dough from bottom to top with your own weight.
Press it about every 1cm and press it into a flat caterpillar bread shape.
Take out the dough, roll it out, or fold it in half or three times, put it in a dense bag, and repeat steps 4-5.
Repeat steps 4-6. After about 8 times, the dough began to become smooth, but the hardness remained basically unchanged. Take out the dough, fold it into dense bags, seal it, and stir it at room temperature 10 minute.
10 minutes later, the dough began to become slightly soft. Press the dough and knead the four corners in the middle to make it round. If the dough can't be rounded, pour some water in the gap and put it in a dense bag to seal it. Let it stand at room temperature for 2 hours.
After 2 hours, take out the dough, sprinkle some dry flour on the chopping block, press the dough long according to the previous 4-6 steps, rotate it for 90 degrees, continue to press the short edge, press the dough slowly for a few times, and then roll it flat.
Slowly, the dough will become more difficult to roll. At this time, it is necessary to sprinkle dry flour on the surface of the flour cake, roll the flour cake on the chopping block in the curling direction on the rolling pin, slowly spread the flour cake, spread it out at a time, and rotate it for 90 degrees to continue rolling the flour cake. After repeated several times, roll the cake to the thickness of1mm.
Sprinkle dry flour on the bread in several parts to facilitate stacking.
Shred, pay attention to sprinkle some dry flour on the cut surface to prevent adhesion.
After boiling, add udon noodles and cook for about 12 minutes.