Masterclass tempura prawns

Mix the mayonnaise with the wasabi paste. Set aside. Remove the shells from the prawns – hold one edge of the shell on the underside where the legs are and peel the other side away from the body in as large pieces as possible. Leave on the tails – you can use them to hold the prawns while cooking and eating them.

Using a small, sharp knife, make a shallow cut along the curved top side of the prawn. You’ll see a thin vein (this may be black or clear). Hook it out with the knife and discard. Rinse the prawns under cold running water and pat dry with kitchen paper. Meanwhile, start to heat the oil in a deep-fat fryer or large pan. If you have a thermometer, heat until the oil is 180C. Or drop in a cube of bread – if it turns golden in 30 seconds, the oil is hot enough.

While the oil is heating, sift the flour, cornflour, baking powder and salt into a bowl and make a well in the centre. Using a wire whisk, gradually mix in the cold sparkling water. Whisk from the centre outwards, to make a thick batter. Don’t over-whisk it though (see tip below).

Put the remaining flour in a shallow bowl. Holding them by the tail, dip the prawns in, one at a time, to coat. Shake off any excess, then dip in the batter.

Carefully put the battered prawn in the hot oil. You can cook a few at a time if your pan is large enough. Cook for 2–3 minutes until golden and crisp.

Use a slotted spoon to remove from the oil and put on a plate lined with a double layer of kitchen paper. Keep warm while you cook the rest. Serve immediately with the wasabi mayonnaise.

Tips:
To thaw the prawns, put them in a single layer in a shallow dish lined with kitchen paper, then leave in the fridge for 4-5 hours. Once thawed, use within 24 hours.

Tempura batter should be mixed quickly and used immediately so that it doesn't lose the air and lightness from the bubbles in the water and the baking powder. To avoid over-beating, mix it with a wire whisk or chopsticks. It should be lumpy and about as thick as double cream.

Keep an eye on the oil and never leave it unattended. If it overheats, it could catch fire.

Use raw prawns rather than ready-to-eat ones so that they don't overcook as they fry and become tough.