Add raw cornflakes to water for a few seconds only. Drain immediately and let extra water pass through the sieve.
Transfer the drained cornflakes to an air fryer-safe tin. Spray lightly with oil and air fry at 170°C for 5 minutes, or until crisp. Keep aside.
Soak thin poha briefly and drain well. Spread it in the same tin and air fry at 170°C for 8 to 10 minutes. Stir once or twice while cooking.
In an air fryer-safe bowl, mix peanuts, roasted Bengal gram, mustard seeds, curry leaves, dried red chillies and oil.
Air fry this tempering mix at 170°C for 5 to 6 minutes, until the peanuts are roasted and the curry leaves turn crisp. Add raisins at the last cook for maximum 1 minute.
Add the crisp cornflakes, poha and peanut tempering to a large mixing bowl.
Add turmeric, chaat masala, amchur, mint powder, red chilli powder, salt and sugar if using.
Mix gently with a spoon until the masala coats the chivda evenly.
Let the air fryer cornflakes chivda cool completely before storing it in an airtight container.