Heat a saucepan over medium-high heat and drizzle in olive oil. Add chopped onion and minced garlic, sautéing until golden brown and fragrant.

Stir in canned tomatoes, tomato paste, oregano, basil, red pepper flakes, salt, and pepper. Let it boil before adding white wine. Simmer for 10 minutes.

In a food processor, purée shrimp until smooth. Transfer to a mixing bowl, and fold in chopped onion, garlic, beaten egg, and bread crumbs.

Fill each cleaned squid tube with shrimp stuffing, leaving the ends unstuffed. Secure open ends with toothpicks if necessary.

Dust stuffed squid with batter mix. Heat olive oil in a pan and brown squid on both sides for 2-3 minutes.

Place browned squid into simmering tomato sauce, cover, and cook for 20 minutes.

Optionally, fry reserved squid tentacles in oil until golden brown and crispy.

Arrange stuffed squid over tomato sauce. Garnish with fried tentacles and parsley before serving.