Step 1

For the Toasted Breadcrumbs: If using fresh or lightly stale bread, adjust oven rack to middle position and preheat oven to 325°F (165°C). (If using fully stale and dried bread, skip baking step.) Arrange bread in single layer on rimmed baking sheet and bake until completely dried, 20 to 30 minutes. Remove from oven and allow to cool to room temperature, about 5 minutes. Transfer bread to food processor bowl (set aside but don't clean rimmed baking sheet), and pulse until reduced to small crumbs, taking care not to over-process into a fine powder, 8 to 10 pulses.

Step 2

Combine breadcrumbs and 1 tablespoon (15ml) oil in a large skillet and cook over medium-low heat, stirring and tossing occasionally, until crisp and golden brown, 8 to 10 minutes. Season lightly with salt. Transfer toasted breadcrumbs to reserved rimmed baking sheet, spread into an even layer, and set aside to cool to room temperature; wipe out skillet. Once cool, set aside 1/2 cup (60g) toasted breadcrumbs for the pasta, and transfer remaining crumbs to an airtight container for future use; the extra breadcrumbs can be stored at room temperature for up to 2 weeks.

Step 3

For the Pasta: Bring a pot of salted water to a boil over high heat. Add cauliflower and cook at a rapid simmer, stirring occasionally, until floret pieces are very tender and offer no resistance when poked with a paring knife at thickest part of stem end, about 10 minutes. Using a spider skimmer, fine-mesh strainer, or slotted spoon, drain cauliflower while keeping boiling water in the pot; transfer cauliflower to a bowl or plate and set aside.

Step 4

Meanwhile, heat 1/4 cup (60ml) oil in now-empty skillet over medium heat until shimmering. Add onion, season lightly with salt, and cook, stirring frequently, until softened but not browned, 5 to 7 minutes. Add anchovies and cook, stirring and breaking up anchovies occasionally with a wooden spoon, until anchovies have dissolved, about 4 minutes.

Step 5

Add cauliflower to skillet along with 1 cup (240ml) reserved cooking water, raisins, pine nuts, saffron, and fennel pollen (if using). Season lightly with salt, bring to a rapid simmer over medium-high heat, and cook, stirring and breaking up cauliflower with a wooden spoon, until florets break down to form a thick, yellow-tinged sauce (thanks to the saffron), 8 to 10 minutes. Add more cooking water in 1/4-cup (60ml) increments as needed to ensure there is enough liquid in the pan to coax cauliflower into breaking down into a saucy consistency.

Step 6

Meanwhile, cook pasta in the reserved pot of boiling water used for cooking the cauliflower until pasta is just shy of al dente (about 2 minutes less than the package directs). Using a spider skimmer (or tongs if cooking bucatini), transfer pasta to sauce, along with 1/2 cup (120ml) pasta cooking water. Alternatively, drain pasta using a colander or fine-mesh strainer, making sure to reserve at least 1 cup (240ml) pasta cooking water.

Step 7

Increase heat to high and cook, stirring and tossing rapidly, until pasta is al dente and cauliflower has broken down even further so that sauce coats noodles and pools around edges of the pan, about 2 minutes; add more pasta cooking water in 1/4-cup (60ml) increments as needed to achieve desired consistency.

Step 8

Remove from heat, add half of the breadcrumbs (1/4 cup; 30g), and toss to combine. Pasta should be well-coated but not swimming in sauce (the sauce will continue to tighten up in the time it takes to plate and serve). Adjust sauce consistency as needed with more pasta water if it seems too dry. Divide pasta between individual serving bowls, sprinkle with remaining breadcrumbs, and serve right away.