Clean the chilli, cut lengthwise, remove seeds, wash and cut into fine rings. Remove the outer leaves of the lemon grass, cut the stalks in half. Wash galangal, cut into pieces. Wash coriander, shake dry, pluck off leaves and put aside (do not throw away the stems!).
Rinse chicken filet, dab dry and cut into bite-sized pieces.
Coconut milk, 3⁄4 Bring l water and broth to the boil in a pot. Add chilli, lemongrass, galangal, coriander stems with roots, lime leaves and chicken. Bring to the boil again and simmer for about 10 minutes.
Clean the mushrooms, possibly wash and halve them. Wash the tomatoes. Sort the sprouts, wash and drain them. Add the sprouts, mushrooms and tomatoes to the soup and simmer for about 5 minutes.
Wash organic lime hot and cut into slices, squeeze the other lime. Season soup with fish sauce and 2-4 tablespoons lime juice.
Remove lemongrass, galangal, coriander stalks and lime leaves from the soup. Garnish soup with coriander leaves and lime wedges.