01 - Slice calamari tubes into ½-inch rings and pat dry with paper towels.
02 - Combine calamari, buttermilk, 1 tsp salt, and ½ tsp black pepper in a bowl. Refrigerate and marinate for 15 minutes.
03 - Heat olive oil over medium heat. Add garlic and sauté for about 1 minute until fragrant. Stir in crushed tomatoes, oregano, basil, red pepper flakes, sugar, salt, and black pepper. Simmer uncovered for 10–12 minutes, stirring occasionally. Adjust seasoning and keep warm.
04 - In a shallow bowl, combine flour, cornstarch, smoked paprika, garlic powder, cayenne pepper, and ½ tsp salt.
05 - Heat vegetable oil in a deep pot or fryer to 350°F (180°C).
06 - Remove calamari from marinade, allow excess buttermilk to drip off. Dredge calamari in the breading mixture, coating evenly and shaking off excess.
07 - Fry calamari in batches for 1½ to 2 minutes until golden and crisp. Avoid overcrowding the fryer.
08 - Drain fried calamari on paper towels and lightly season with salt while still hot.
09 - Serve immediately alongside warm marinara sauce, lemon wedges, and sprinkle with fresh parsley if desired.