Coat the chicken with 1 tablespoon of tapioca flour. Mince garlic. In a bowl, add water to the rest of flour. This will the base for sauce. Cut up the Chinese broccoli and cauliflower into 2 inch-pieces.
Heat up 4 tablespoons of oil in a non-stick pan,put in the noodles and stir. Add 2 tablespoons of dark soy sauce on the noodles.Keep stirring for 5 more minutes. Set the cooked noodles aside.
Cooking The Meat and Gravy: heat up the oil. Add minced garlic and coated chicken. Stir for a minute or so until the chicken is getting cook. Add the flour water. Stir quickly to keep it from forming chunks. When cooked, the flour will turn from white to clear. Add soy sauce, yellow bean sauce and sugar. Stir. When the sauce is bubbling, it should have a consistency of thick gravy.
Add Chinese broccoli. Stir quickly and turn the heat off. Put noodles on plates and top with the sauce. Sprinkle some ground white or black pepper.
In Thailand, Rad Nah is served with sugar, fish sauce, peppers pickled in white vinegar and ground chilli pepper for your personal taste.
Tips and substitutions
You can substitute any meat, tofu or seafood for the pork or omit it altogether.
If you can't find Chinese broccoli, try collard greens, broccoli, cauliflower.
Some people add bean sauce. If you do, add 2 tablespoons and reduce soy sauce to 2 tablespoons.