If not already cleaned, rinse squid tubes and tentacles under cold water. Pat thoroughly dry with paper towels. Slice tubes into 1/2-inch rings. Leave tentacles whole or halve if very large. Drying the squid well is critical for a crispy coating.

Make the dry mix

In a large bowl combine all-purpose flour, cornstarch, 1 tsp fine sea salt, 1/2 tsp black pepper, smoked paprika, and garlic powder. Whisk to uniform distribution.

Prepare wet binder

In a separate bowl whisk cold sparkling water with the egg (if using). The sparkling water keeps the batter light. If you prefer not to use egg, use all sparkling water.

Coat the calamari

Add squid rings and tentacles to the dry mix and toss to lightly coat. Shake off excess. Transfer about half the coated squid to the wet binder and toss quickly to moisten. Remove from wet binder and return to the dry mix, tossing to form a thin, even dry batter. Repeat with remaining squid. This double-coating gives an extra-crispy crust.

Heat the oil

Pour oil into a heavy-bottomed pot or deep fryer to a depth of about 2–3 inches (about 3–4 cups depending on vessel). Heat oil to 350°F (175°C). If you do not have a thermometer, test with a small pinch of flour: it should sizzle and turn golden quickly but not burn.

Fry in batches

Carefully lower a single layer of coated calamari into the hot oil using a spider or slotted spoon. Fry 1 to 1 1/2 minutes—just until the coating is golden and the squid is opaque and slightly firm. Avoid overcooking which makes squid rubbery. Remove with a skimmer and drain on paper towels or a wire rack. Sprinkle immediately with a little extra salt if desired. Repeat with remaining calamari, keeping completed batches warm in a low oven (200°F / 95°C) if needed.

Finish and serve

Transfer fried calamari to a serving plate. Squeeze lemon wedges over the top and sprinkle with chopped parsley if using. Serve immediately alongside the aioli for dipping.

Aioli

In a small bowl combine mayonnaise, minced or grated garlic, lemon juice, Dijon mustard, extra-virgin olive oil, salt, and pepper. Whisk until smooth. Taste and adjust seasoning—add up to 1 tsp more lemon juice for brightness, or a pinch more salt.

If the aioli is too thick, whisk in water 1 teaspoon at a time until it reaches a creamy, spoonable consistency that will cling to the calamari.

Cover and refrigerate until ready to serve. Remove from refrigerator 10 minutes before serving to take the chill off and allow flavors to open.