Fried Calamari

• Vegetable oil, for deep-frying
• 1 pound clean squid with tentacles, bodies cut into 1/3- to 1/2-inch-thick rings
• 2 cups all-purpose flour
• 2 tablespoons dried parsley
• Salt and freshly ground black pepper
• 2 lemons, cut into wedges
• 1 cup simple tomato sauce, recipe follows or jarred marinara sauce, warmed

Simple Tomato Sauce:

• 1/2 cup extra-virgin olive oil
• 1 small onion, chopped
• 2 cloves garlic, chopped
• 1 stalk celery, chopped
• 1 carrot, chopped
• Sea salt and freshly ground black pepper
• 2 (32-ounce) cans crushed tomatoes
• 2 dried bay leaves
• 4 tablespoons unsalted butter, optional