This warming soup really packs a flavorful punch.
Soak the noodles in a bowl of hot water until pliable, about 5 minutes.
Meanwhile, in a large saucepan, heat the oil until shimmering. Add the shiitake and cook over high heat, stirring occasionally, until lightly browned, 2 to 3 minutes. Add the garlic and ginger and cook, stirring, for 30 seconds. Add the stock and bring to a boil.
Drain the noodles, add them to the saucepan and cook over moderate heat just until tender, about 3 minutes. Add the pork, vinegar, soy sauce and chile-garlic sauce and simmer until the pork is nearly cooked through, about 2 minutes. Add the snow peas, scallions and cornstarch mixture and cook until the vegetables are crisp-tender, about 1 minute. Stir in the sesame oil and season with salt. Ladle the soup into bowls and serve.