Wash and pat dry the fish. Cut into 2-inch x 1 1/2-inch pieces.
Blend the onion, garlic, ginger, coriander, lemon juice and salt until the mixture is a smooth paste.
Coat the fish pieces with a light coating of the paste. Marinate in the refrigerator for 2-3 hours.
Mix the flour, salt and chili powder together. Spread in a plate. Dip the fish pieces in the beaten egg.
Then lightly toss them in the flour mixture.
Heat the oil in a frying pan over medium heat until hot. Gently lay the fillets into the hot oil. Fry until golden brown on both sides. Place them on a paper towel to absorb extra oil. Serve the Masala Machchi with rice or salad.