Instructions:
- Mix coating: In a bowl, combine cornflour, plain flour, salt, and pepper. Whisk in water gradually to create a thin, smooth batter—it should coat the back of a spoon lightly.
- Coat: Gently toss the paneer cubes in the batter until lightly coated. Let them sit for 5 minutes.
- Fry: Heat oil in the wok until shimmering (around 350°F/175°C). Fry the paneer in batches until golden brown and crisp. Do not overcrowd the pan.
- Drain: Remove fried paneer with a slotted spoon and drain thoroughly on paper towels. Set aside.
- Sauté Aromatics: Drain most of the frying oil, leaving about 1 Tbsp in the wok. Heat over high heat. Add minced garlic, ginger, and slit green chillies. Stir-fry rapidly for 30 seconds until fragrant.
- Cook Vegetables: Add the onion and bell pepper wedges. Stir-fry vigorously over high heat for 1-2 minutes until they are crunchy.
- Add Sauces: Push the vegetables to one side. Add soy sauce, red chilli sauce, ketchup, vinegar, sugar, and black pepper to the clear space in the wok. Let the sauce bubble for 15 seconds.
- Combine: Toss the vegetables quickly through the sauce. If using the optional slurry, pour it in now and toss until the sauce just thickens slightly.
- Final Toss: Return the crispy paneer to the wok. Toss everything together very quickly (about 30 seconds) to ensure the paneer is coated but remains crisp.
- Finish: Stir in the white parts of the spring onions. Transfer immediately to a serving dish and garnish generously with the green spring onion tops.