01 - Slice the cleaned squid into 0.4-inch rings; halve any large tentacles.
02 - Place squid in a bowl and toss with sea salt, black pepper, and lemon juice. Let rest for 10 minutes.
03 - Whisk together flour, cornstarch, baking powder, and cayenne pepper in a medium bowl.
04 - Gradually whisk in the cold sparkling water until the batter is smooth yet thick enough to coat.
05 - Heat vegetable oil in a deep pan or fryer to 350°F (180°C).
06 - Pat marinated squid dry with paper towels. Dip each piece into the batter, letting excess drip off.
07 - Fry squid in batches for 2 to 3 minutes until golden and crisp.
08 - Remove with a slotted spoon and drain on kitchen paper. Serve immediately with lemon wedges and parsley sprinkle.