Take 500 grams of boneless fish fillets (preferably white fish like basa or cod) and cut them into finger-sized strips.
In a bowl, mix 1 teaspoon ginger-garlic paste, 1 teaspoon red chili powder, 1/2 teaspoon turmeric powder, 1/2 teaspoon garam masala, salt to taste, and 1 tablespoon lemon juice. Marinate the fish fingers in this mixture for 20-30 minutes.
In another bowl, prepare a batter by mixing 1/2 cup besan (gram flour), 1/4 cup cornflour, 1/2 teaspoon red chili powder, 1/4 teaspoon black pepper powder, salt to taste, and water as required to form a thick, smooth batter.
Spread 1 cup breadcrumbs on a plate.
Heat oil in a deep frying pan for deep frying.
Dip each marinated fish finger in the batter, ensuring it is evenly coated, then roll it in the breadcrumbs, pressing gently to ensure the breadcrumbs stick well.
Carefully place the coated fish fingers in the hot oil and deep-fry them until they turn golden brown and crispy. Fry in batches to avoid overcrowding the pan.
Remove the fried fish fingers from the oil using a slotted spoon and place them on a paper towel to drain excess oil.
Serve hot with mint chutney or ketchup.