Cook rice in 1⁄2 l boiling salt water according to package instructions.
Clean the celery, putting the light green aside for garnishing. Wash the stalks and cut them into 1 cm wide pieces. Peel and halve the onion and cut into thin slices.
Carefully clean the mushrooms, cut away hard spots. Do not wash the mushrooms as they are very sensitive to pressure. Cut mushrooms into 1-2 cm wide strips. Heat oil in a pan and fry the mushrooms in it.
Reduce heat. Add onion and celery and stir-fry for about 3 minutes. Season with salt, pepper and coriander. Add lemon juice. Simmer for another 3-5 minutes. The celery should be firm to the bite.
Just before serving, fold in soy cream and season with soy sauce. Sprinkle with chopped celery green. Serve with rice.