1.Heat the oil for deep-frying in a deep non-stick pan, and deep-fry the potatoes on medium flame till they turn golden brown in colour from all the sides.
2.Drain on an absorbent paper and keep aside.
3. Combine the cornflour and ¾ cup of water in a deep bowl, mix well and keep aside.
4.Heat the oil in a broad non-stick pan, add the ginger, garlic and green chilies and sauté on a medium flame for 30 seconds.
5. Add the onions and sauté on a medium flame for 1 minute.
6. Add the capsicum and sauté on a medium flame for 1 minute.
7. Add the mushrooms and salt, mix well and cook on a medium flame for 2 minutes, while stirring occasionally.
8. Add the soy sauce, cornflour-water mixture, mix well and cook on a medium flame for 1 minute, while stirring continuously.
9. Add the deep-fried potatoes, toss gently and cook on a medium flame for 1 minute.
10. Serve immediately.