Chef John's Pasta Con Le Sarde

Cook and stir bread crumbs with 2 tablespoons olive oil in a skillet over medium heat until bread crumbs are crispy and toasted, 2 to 5 minutes.

Transfer breadcrumbs to a bowl to cool.

Grind saffron threads with a mortar and pestle; pour white wine into mortar and stir to combine.

Bring a large pot of lightly salted water to a boil.

Cook bucatini in boiling water, stirring occasionally until almost cooked through but firm to the bite, 10 to 11 minutes.

Drain, reserving 1/2 cup of the pasta water.

Heat remaining olive oil in large skillet over medium heat.

Cook and stir onion and fennel with a pinch of salt in hot oil until onion is soft, about 10 minutes.

Stir raisins, garlic, and anchovy fillet into onion mixture; cook and stir until heated through, about 1 minute.

Pour saffron-wine into skillet; cook until wine is almost evaporated, about 2 minutes.

Pour 1 ladleful reserved pasta water into skillet and bring to a simmer.

Stir pine nuts and red pepper flakes into sauce; simmer until flavors combine and sauce is reduced, about 5 minutes.

Stir bucatini and sardines into wine mixture; increase heat to high, and cook, stirring frequently and adding more reserved pasta water as necessary, until sauce and pasta are heated through, about 5 minutes.

Remove from heat.

Ladle into bowls and top with fennel fronds and toasted bread crumbs.