Heat oil, splutter mustard seeds and cumin seeds. Add chopped onions and fry until onions are pink. Put in chopped capsicum and chopped cabbage to it and saute until cabbage is cooked.
Put in 2-3 tbsp leftover curry, chilli powder and garam masala. Adjust salt. Drop the chapati pieces in along with tomato sauce and soya sauce.Mix well and let it cook for a min or two and serve hot topped with chopped spring onion.