Heat 3 tsp oil in a wok. Drain and sqeeze the banana flowers and add to the wok. Stir fry for 5 mins. Remove from wok and transfer to a pressure cooker. Cut the rest of the vegetables into small pieces and add to the pressure cooker. Grind the mustard seeds and half of the garlic flakes into a smooth paste. Add to the pressure cooker along with a little bit of water. Add the green chillis ( slit into 2 ), remaining garlic flakes, mustard oil, salt and a pinch of turmeric. Mix the contents of the pressure cooker and close the lid. Put on stove and allow to cook for 2 whistles. Allow steam to escape. Open the lid and check if there for excess water remaining. If so, put back on stove and cook on a high flame with lid open to evaporate the water. Serve with rice