Whisk the flour, cornstarch, ginger-garlic paste, chili powder, and salt together. Add water gradually until you get a thick paste that coats the back of a spoon — thick enough to cling to the florets without dripping off. Toss the cauliflower florets in the batter until each piece is evenly coated.

Preheat your air fryer to 380°F (193°C) for 3–4 minutes. Arrange the battered florets in a single layer in the basket, leaving space between pieces — crowding steams them instead of crisping them. Spray the tops lightly with oil. Air fry for 12–14 minutes, shaking or flipping the basket halfway through, until golden and crisp on the outside.

Build the sauce. While the cauliflower cooks,

heat sesame oil in a pan over medium-high heat. Add garlic and ginger, sauté for 30 seconds until fragrant (don't let it brown). Add onion and green pepper, stir-fry for 2 minutes — you want them slightly softened but still with a bite, not mushy. Add green chilies if using.

Lower the heat slightly and stir in soy sauce, ketchup, chili sauce, vinegar, and sugar. Add water depending on whether you want dry or gravy style. Let it simmer for a minute.

Stir in the cornstarch slurry and cook for another 30–60 seconds until the sauce turns glossy and coats the back of a spoon.

Add the crispy air-fried cauliflower straight into the pan. Toss quickly on high heat for 30–45 seconds so the florets soak up the sauce but stay crisp — don't let it sit in the sauce for long, or it'll go soft. Garnish with spring onion greens and serve immediately.