Heat oil in a kadai and add cumin seeds. When they begin to change colour, add green chillies and ginger paste. Sauté for half a minute. Add potatoes and cauliflower and stir. Sauté for two to four minutes.
Add turmeric powder, red chilli powder and salt and mix. Add yogurt and mix again, cover and cook on medium heat till done. Add ginger strips and stir well. Add tomato and stir. Garnish with coriander leaves and serve hot.