Place the cleaned calamari in a large bowl and pour the buttermilk over the top. Toss until evenly coated, cover, and refrigerate for at least 30 minutes.
Fill a deep pot with about 3 to 4 inches of vegetable oil and heat it to 375°F (190°C).
While the oil heats, whisk together the flour, salt, paprika, garlic powder, and black pepper in a shallow bowl.
Remove the calamari from the buttermilk, allowing any excess to drip away. Dredge each piece thoroughly in the seasoned flour, shaking off any extra coating.
Working in small batches, carefully lower the coated calamari into the hot oil. Fry for 2 to 3 minutes, just until lightly golden and crispy. Avoid overcooking, as calamari becomes chewy very quickly.
Transfer the fried calamari to a wire rack or paper towel-lined tray to drain while repeating with the remaining batches.
Sprinkle immediately with a little extra salt and fresh parsley.
Serve hot with lemon wedges and your favorite dipping sauce.