This delicious recipe is courtesy of Vincent Nargi from Cafe Cluny.
Preheat oven to 450 degrees. Thinly slice 3 cloves garlic. Heat 1/4 cup olive oil in a large skillet over medium heat. Add garlic, anchovies, and red pepper flakes; cook until garlic has browned. Stir in tomatoes; transfer to oven and roast until dried and thickened, about 20 minutes.
Add reserved tomato juice to cooked tomato mixture and stir to reconstitute sauce. Add capers, basil, pine nuts, and raisins; stir to combine. Season with salt and pepper; place over low heat to keep warm.
Heat a large skillet and add 3 tablespoons olive oil; heat until smoking. Add squid, cook, stirring constantly, until squid rings begin to open up and become firm, about 30 seconds. Season with salt and pepper. Add tomato sauce to skillet, bring to a boil, then reduce to a simmer. Cook until squid is opaque and sauce is hot, 2 to 3 minutes.
Preheat a grill pan. Drizzle bread with 3 tablespoons olive oil and season with salt and pepper. Grill until toasted on both sides. Rub cut sides of toasted bread with remaining clove of garlic.
Divide calamari evenly among 4 shallow bowls. Drizzle with olive oil and sprinkle with lemon zest and parsley. Serve immediately with toasted bread.