Saute onions, potatoes, celery, turnip, carrot and sweet potato until they begin to sweat. Add stock, bay leaf, garlic, ginger, soup mix and chilli. Bring to boil, reduce heat and simmer for 1 hour.
Add bok choy and cumin, simmer for a further 10 minutes. Remove bay leaf and season with pepper and salt, if desired.
Chicken stock may be used instead of vegetable stock.