Prepare the Tempura Batter

1. In a bowl, lightly beat the egg. Add the ice-cold sparkling water and gently stir, being careful not to lose too much of the carbonation. Add the flour, cornstarch and salt, then mix lightly until just combined. A few small lumps are perfectly fine—they help create an extra crispy batter. Keep the batter chilled in the refrigerator until ready to use.
2. Meanwhile, prepare the shrimp by removing the heads and shells. Using a toothpick, carefully remove the dark vein from the back of each shrimp. Make two small cuts on the underside where the shrimp naturally curls, then gently press it against a work surface to straighten it. This helps prevent the shrimp from curling while frying. Repeat with the remaining shrimp.
3. Place the shrimp in a bowl and season with the salt, black pepper, garlic powder, paprika, lime zest and lime juice. Toss well and leave to marinate for 10–15 minutes.
4. Heat the sunflower oil in a deep frying pan or saucepan. Dip each shrimp into the chilled tempura batter and fry for 2–3 minutes, turning once halfway through, until golden, light and crispy. If the oil becomes too hot, slightly reduce the heat so the batter cooks through properly without browning too quickly. Transfer the fried shrimp to a plate lined with paper towels to drain.

Prepare the Sweet Chili Mayo

1. In a small bowl, combine the mayonnaise, Sweet Chili Sauce, Sriracha and lime juice. Stir until smooth.
2. Serve the tempura shrimp immediately while hot and crispy, alongside the Sweet Chili Mayo for dipping.