Dry roast coriander seeds, fennel, cumin, and dried red chilies in a small pan over low heat until fragrant and slightly dark.
Let the toasted spices cool, then grind them into a coarse powder using a mortar and pestle or spice grinder.
Heat 1 tbsp oil in a pan. Flash-fry paneer cubes, bell pepper squares, and onion petals for 2 minutes. Remove and set aside.
Add remaining oil to the same pan. Sauté chopped onions until golden brown, then stir in ginger-garlic paste for 1 minute.
Add tomato purée and half of the freshly ground Kadai Masala. Cook until oil separates from the sides of the paste.
Pour in a splash of water to loosen the gravy. Fold in the seared paneer and veggies, and simmer gently for 3 minutes.
Sprinkle the remaining Kadai Masala and crush kasuri methi over the hot curry. Serve immediately.
