Dry roast the rava with little ghee or oil until you can smell the aroma but don't let it burn. Heat the oil in a thick saucepan. Add the mustard seeds and after they pop add the urad dal. When it turns slightly brown add green chilies and onion and saute till it softens. Add the vegetables and saute some more. Add 4 cups of water, salt and hing. When the water boils add the rava while stirring constantly. After 2 or 3 min, cover the pan and cook over a low flame for 7 minutes. Serve hot or warm.