Add 4g salt to 400g all-purpose flour and add 200ml of warm water to it. Add another 10-20ml of water if needed. Knead for 1-2 minutes until it is a rough ball shape. Cover for 10 minutes. Dough should be fairly easy to knead but not too soft
Continue kneading the dough for a few minutes until smooth and roll into a ball again and cover for 30 minutes
Marinade the pork with 1 tsp light soy sauce, 1 tsp sugar, ½ tsp salt, 1 tsp cornstarch and 1 tsp cooking wine. Marinade for 10 minutes
Wash and cut napa cabbage and shitake mushrooms and set aside
Add 1 tbsp oil to a pan or pot and brown the pork on medium-high heat until cooked. Remove from heat and set aside
Pour the 1 liter of broth into pot and turn heat to high. When the broth boils, add napa cabbage and shitake and cook until broth boils again. Turn the heat down to medium, the broth should be simmering or have little bubbles. You may choose to remove some or all the vegetables from the broth so that you have more room to cook the noodle flakes. Removing the vegetables will also prevent the vegetables from becoming too soft from overcooking. However, some people like very soft napa cabbage too
Add 1 tsp of oil to the dough ball and rub over the outside of the dough. This will help improve the texture of the noodle flake as well as preventing it from sticking to your fingers when pulling off the pieces
Pull off a chunk of the dough and keep the remaining covered
Pull off a piece of the dough, flatten it with your fingers and drop it into the simmering broth. The noodle flakes should be approx. 2.5 cm or 1” in size but they can be any shape, any size but try to flatten them to prevent from having any uncooked pieces. Repeat this process until all the dough is used
Once all the noodle flakes have been put into the pot, pour the meat and vegetables back into the pot and stir well
Turn heat to medium-high or high and cover the pot with a lid and wait for it to boil
Once it boils again, it will be ready to serve
Taste the broth, add salt and/or soy sauce to achieve desired saltiness Since some broth come salted and some unsalted, you can determine how much salt you want to add