Step 1

In a medium bowl, whisk together milk and salt. Add squid and toss to coat. Cover and refrigerate squid for at least 30 minutes and up to 2 hours.

Step 2

In a large bowl, whisk together flour, cornstarch, pepper, and baking powder until thoroughly combined, about 30 seconds. Set aside.

Step 3

Set a wire rack in a rimmed baking sheet and place a colander on top of the rack. Set a second wire rack in another rimmed baking sheet and line rack with paper towels. Heat oven to 200°F (95°C).

Step 4

Using clean hands, remove half of squid from milk mixture, allowing excess liquid to drain back into bowl, then transfer to flour mixture. Toss squid to coat evenly. Gently shake off excess flour and transfer squid to colander set over wire rack. Shake colander to sift out any excess flour, then transfer squid in a single layer to wire rack. Repeat with remaining squid. Let dredged squid rest for 15 minutes.

Step 5

Meanwhile, heat oil in Dutch oven or wok over high heat to 365°F (185°C). Add half of squid and fry until golden brown, stirring occasionally to prevent pieces from sticking to each other, about 3 minutes (the oil temperature will drop significantly once the squid is added; adjust heat to maintain temperature between 275-300°F/135-150°C).

Step 6

Using a slotted spoon or spider, transfer calamari to prepared paper towel–lined rack, season lightly with salt, then transfer to oven to keep warm.

Step 7

Skim any browned bits from oil and discard. Return oil to 365°F (185°C) and repeat with remaining squid.

Step 8

Transfer calamari to plate and serve immediately with red sauce and lemon wedges.