1: Pat the crayfish tails dry with kitchen paper and set aside.

2: Heat about a 12cm depth of oil in a deep-fat fryer to 180C. Or use a large, deep pan, making sure it is no more than a third full as the oil will bubble up ferociously when you add the crayfish. Use a frying thermometer to check the temperature, if you have one; otherwise drop a cube of dry white bread into the hot oil – if the bread turns golden brown in just under a minute, the oil is up to temperature. Keep a close eye on it and never leave the pan unattended.

3: Meanwhile, mix everything for the batter but the water in a large bowl. Whisk in the sparkling water to form a smooth, loose batter.

4: Dust the crayfish in flour to coat evenly but shake off any excess. You will need to fry them in batches. Don’t overcrowd the pan and allow the oil to come back up to temperature between batches. Dip the crayfish into the batter to coat, then lower them into the hot oil and deep-fry for 2–3 minutes until golden brown and crisp.

5: Carefully remove the crayfish 'popcorn’ from the oil using a slotted spoon and drain on a tray lined with kitchen paper. Repeat with the remaining crayfish.

6: Pile the 'popcorn’ up high in a bowl and season with a pinch of smoked paprika and a little salt to taste. Finely grate some of the grapefruit zest on top. Serve immediately, with mayonnaise.