Clean the cauliflower, divide into small florets, wash and drain. Peel, wash and thinly slice the carrots. Clean, wash and thinly slice the celery.
Quarter the white cabbage, remove the outer leaves and the stalk. Cut the white cabbage into bite-sized strips. Peel ginger and cut into thin slices. Peel onion and cut into strips.
Heat the oil in a pot. Sauté onion and ginger tartare. Deglaze with broth. Add white cabbage, carrots, celery and cauliflower and cook for about 10 minutes. In the meantime clean and wash spring onions, dab dry and cut into fine rings.
Season soup with soy sauce and Sambal Oelek, arrange in soup bowls. Sprinkle with spring onions and garnish with coriander.