1. I personally prefer to use dried shiitake mushrooms because I always have them in the pantry and they add a stronger flavor to the dish. Alternatively, you could use fresh shiitake mushrooms or white mushrooms.
2. The recipe uses the stir-fry-and-steam method to create very tender chicken. You could cut large pieces of chicken and not worry about it not cooking through at first. I prefer to slice the chicken breast into 1 cm (1/2 inch) pieces, then cut the large pieces in half.
3. This is the most important step. By covering the skillet and letting it steam, the noodles and vegetables will soak up the sauce and the chicken will be cooked through while retaining its juiciness and tenderness.