Fish coated in batter and fried quickly in hot deep oil is light and the flavour of the fish is preserved. The choice of oil is important not only for the flavour but also because the higher the temperature an oil can reach without developing a ‘burnt’ taste, the better. Vegetable oils are best to use, notably sunflower and groundnut.
For deep-frying fish, the temperature of the cooking oil should be between 180°C and 190°C (350°F and 375°F) or until a cube of white bread browns in about 30 seconds.
To make a simple batter for 4 cutlets or fillets, mix 1 egg and 300ml (½ pint) milk or water with 125g (4oz) seasoned flour until smooth. Milk makes a thicker batter than water.
Prepare the batter and place in a relatively deep bowl. Dip each piece of fish into the batter, then allow the excess batter to drip off. It is best to cook the fish as soon as it is coated, so prepare and dip in batches, depending on how many pieces of fish fit in your frying basket at one time.
Use a deep heavy-based saucepan only one-third full with oil. Heat the oil steadily to the correct temperature, testing with a deep-frying thermometer or bread cube (above). Place the fish in a frying basket that fits the pan comfortably, then lower it in gently. Cook until golden brown and crisp. Drain the fish well on absorbent kitchen paper and keep it warm in a low oven, until all the pieces have been fried and you are ready to serve.