Soak dried wood-ear mushrooms and shiitake mushrooms in hot water for 5-7 minutes or until they are fully rehydrated. Julienned wood-ear mushrooms (we will have about 1 cup). Remove the stems of shiitake mushrooms and keep the mushrooms whole.
Parboil chicken in boiling water for 1-2 minutes. Then take it out and discard the blanching liquid.
In a clean pot, bring 9 cups of water to a boil. Add 2 teaspoons salt, whole shallots, ginger and the white parts of scallion to the pot. Then add the chicken and let the water come back to a boil. Skim off any foam then lower the heat to a gentle simmer. Cover the pot with the lid slightly askew and poach the chicken for about 20 minutes or until the meat is just cooked through.
Transfer the cooked chicken to an ice bath. Once it is cool enough to handle, separate the meat and the bones. Put the bones together with the shiitake mushrooms in the stock pot and continue to simmer the broth for at least another 45-60 minutes. If you have time, simmer the bones for 90-120 minutes for stronger flavors. Shred the meat.
30 minutes before the broth is ready or when you want to serve the dish, soak glass noodles in room temparature water for 20-30 minutes.
Place a skillet over medium heat and heat some oil. Once the oil is hot, add 1 tablespoon minced shallots and cook for about 30 seconds or until very fragrant. Add julienned wood-ear mushrooms and stir and cook briefly. Add 1½ teaspoons fish sauce and a generous amount of black pepper. Stir thoroughly and sauté until the flavors are fused. Set aside.
Once the broth is ready, take the bones out of the broth and increase the heat to bring it to a more rapid simmer. If too much liquid has evaporated, you can add back some hot water to the broth.
Add sautéed wood-ear mushrooms first, then add the noodles to the broth. Cook very briefly (about 30-45 seconds for me but it will depend on the noodles). It is better to slightly undercook the noodles than overcooking it. Taste the broth and adjust seasonings to your likings. Then transfer the noodles to serving bowls.
Place shredded chicken over the noodles. Scatter sliced scallion, cilantro, Vietnamese coriander and sprinkle black pepper on top. Ladle hot broth as well as wood-ear mushroom strips into serving bowls. Serve immediately.