Pour approx. 300 ml of boiling water over the mushrooms, cover and leave to stand for approx. 20 minutes. In the meantime. Clean and wash the beans, cut them into smaller pieces if necessary and cook them in boiling salted water for about 5 minutes until al dente. Take the beans out, rinse them under cold water
Clean, wash and cut off the stalk of Pak Choi. Cut leaves into strips. Peel and finely dice shallots and garlic. Peel and finely chop the ginger. Drain mushrooms, collect liquid. Mix stock, 100 ml mushroom water, 4 tablespoons soy sauce, mirin, shallots, garlic, ginger and starch.
Cook the pasta in boiling salted water according to the instructions on the packet. Drain the pasta, rinse thoroughly with cold water and drain
Heat the oil in a large frying pan. Fry Pak Choi in it for 1-2 minutes. Add noodles, beans and mushrooms and fry for 2-3 minutes more. Stir the stock mixture again, add the noodles and vegetables, bring to the boil while stirring, season to taste with 1-2 tbsp. soy sauce and lime juice and serve