01 - Place calamari rings in a bowl and cover with buttermilk. Allow to marinate for 15 minutes.
02 - Heat olive oil in a saucepan over medium heat. Add minced garlic and sauté for 30 seconds until fragrant.
03 - Add crushed tomatoes, oregano, chili flakes if using, sugar, salt, and pepper. Simmer uncovered for 10 to 12 minutes, stirring occasionally until sauce thickens slightly. Stir in basil and keep warm.
04 - In a shallow dish, mix together flour, cornmeal, garlic powder, paprika, salt, and black pepper.
05 - Heat vegetable oil in a deep fryer or large deep pan to 350°F (180°C).
06 - Remove calamari from buttermilk, letting excess drip off. Dredge in the breading mixture until thoroughly coated.
07 - Fry calamari in batches for 1 to 2 minutes until golden brown and crispy. Avoid overcrowding the pan. Remove and drain on paper towels.
08 - Serve calamari hot with lemon wedges and marinara sauce on the side.