The Batter: In a bowl, mix the mushrooms, ginger-garlic paste, salt, and pepper. Let it sit for 2 minutes. The mushrooms will release a tiny bit of moisture. Now, sprinkle the cornflour and maida dry over the mushrooms. Toss them well. Sprinkle a few drops of water only if needed to coat the flour.
Tip: We want a thin, sticky coating, not a thick pakoda-like batter.
The Fry: Heat oil in a deep pan. When the oil is hot, drop the mushrooms in one by one (don't clump them). Fry on medium-high heat until they are golden and sound hollow when tapped. Drain and keep aside.
The Wok Sear: In a separate wok or wide pan, heat 1 tbsp oil on High Heat. Add the chopped ginger, garlic, and green chilies. Sauté for 30 seconds until the garlic turns golden.
The Crunch Veggies: Add the onion petals and capsicum. Toss on high flame for just 1 minute. They must remain crunchy.
The Sauces: Lower the heat slightly. Add the soy sauce, chili sauce, vinegar, and ketchup. Add a pinch of salt (be careful, soy is salty) and black pepper. Mix well.
The Toss: Add the fried mushrooms to the pan. Increase the heat to high. Toss quickly for 30 seconds so the sauce coats the mushrooms evenly. Do not cook for too long, or they will soften.
Finish: Turn off the heat. Stir in the spring onion greens. Serve immediately. The "Pinch of Thrift" Tip (Zero Waste)
Flavored Oil: After deep-frying the mushrooms, do not discard the oil! Filter it through a sieve. This oil now has the aroma of mushrooms and ginger-garlic.
How to use: Use this oil to make Fried Rice or Stir-fry Noodles the next day. It adds that authentic "restaurant flavor" base that fresh oil lacks.