Take a bowl and mix together corn flour, all purpose flour, salt, soy sauce, vinegar and pepper powder in it. Once the mixture is ready, add the mushrooms in the bowl and mix well.
Heat oil in a deep frying pan over medium flame. Fry the coated mushrooms until golden brown and crisp. Remove and drain the excess oil. Keep 1-2 tsp oil in the pan and remove the excess.
Add ginger, garlic, onions and green chillies in the pan and saute for a minute or two. Once the onions turn slightly translucent, add the red chilli sauce and little water, if desired. Once the red gravy is cooked, add the mushrooms and stir well.
Cook the mushrooms until all moisture has evaporated and then transfer the dish to a serving bowl. Garnish with coriander leaves and spring onions. Pair it with cola or any summer beverage. Enjoy!