In a sauté pan, heat 2 tablespoons of olive oil over moderate heat. Add one clove of minced garlic and sauté until fragrant. Add panko breadcrumbs and stir frequently for about 5 minutes until golden. Remove from heat and mix with Parmesan cheese, salt, and pepper.

In the same skillet, heat the remaining olive oil over medium heat. Add chopped onions, remaining minced garlic, and diced fennel. Sauté until lightly golden, about 10 minutes. Stir in tomato paste and chopped anchovies, if using. Add half of the sardines, breaking them up gently, along with the soaked raisins and saffron with soaking water. Season with salt and pepper, and cook for about 5 minutes.

While the sauce simmers, bring a large pot of salted water to a boil. Add bucatini or thick spaghetti and cook according to package instructions until al dente. Drain the pasta, reserving some cooking water.

Add the drained pasta to the skillet with the sardine mixture. Pour in about a cup of reserved pasta cooking water and stir well to coat the pasta. If the sauce is too dry, add more reserved water until desired consistency is reached. Gently fold in remaining sardines and chopped fennel fronds.

Plate the St. Joseph's Spaghetti and generously top with the crispy breadcrumb mixture. Serve immediately.