Dry-roast 3 tablespoons of coarse chickpea flour (besan) in a frying pan, stirring, until it no longer smells raw. Let it cool and set a little aside for sprinkling.
Mix the rest with ¾ teaspoon of red chili powder, ¾ teaspoon of garam masala, ¼ teaspoon of turmeric, ½ teaspoon of crushed kasuri methi (dried fenugreek leaves), and ½ teaspoon of amchur (dried mango powder).
Stir in 1 teaspoon of ginger-garlic paste, ⅓ teaspoon of salt, 1 teaspoon of lemon juice, and 2 tablespoons of plain yogurt. Coat 300g of salmon fillets with the paste and rest for 10 minutes.
Heat 2 tablespoons of oil in the pan and add ¼ teaspoon of carom seeds (ajwain). Fry the fish for 4 minutes.
Sprinkle the reserved flour over the top, turn, and fry for 5 minutes more, until crisp and the fish reaches 145°F / 63°C.
