Preparation Smash ginger and garlic with flat side of a heavy knife, then combine with stock and 3 cups water in a 4-quart heavy saucepan. Simmer, uncovered, 5 minutes. Remove skin and excess fat from chicken thighs and add to stock mixture with salt. Simmer, uncovered, until chicken is cooked through, 25 to 30 minutes. Meanwhile, soak mushrooms in 2 cups boiling-hot water in a small bowl 15 minutes, then drain and thinly slice, discarding stems. Transfer chicken with a slotted spoon to a cutting board. Shred meat into 1/4-inch-thick pieces. Skim fat from broth and discard ginger and garlic. Stir mushrooms and noodles into broth and simmer, uncovered, until noodles are translucent, about 6 minutes. Cut greens of scallions into 1 1/2-inch pieces and stir into broth along with chicken. Simmer, uncovered, until noodles have absorbed most of broth, about 2 minutes. *Available at Asian markets and Uwajimaya (800-889-1928).
Preparation Smash ginger and garlic with flat side of a heavy knife, then combine with stock and 3 cups water in a 4-quart heavy saucepan. Simmer, uncovered, 5 minutes. Remove skin and excess fat from chicken thighs and add to stock mixture with salt. Simmer, uncovered, until chicken is cooked through, 25 to 30 minutes. Meanwhile, soak mushrooms in 2 cups boiling-hot water in a small bowl 15 minutes, then drain and thinly slice, discarding stems. Transfer chicken with a slotted spoon to a cutting board. Shred meat into 1/4-inch-thick pieces. Skim fat from broth and discard ginger and garlic. Stir mushrooms and noodles into broth and simmer, uncovered, until noodles are translucent, about 6 minutes. Cut greens of scallions into 1 1/2-inch pieces and stir into broth along with chicken. Simmer, uncovered, until noodles have absorbed most of broth, about 2 minutes. *Available at Asian markets and Uwajimaya (800-889-1928).