Gemelli with Cauliflower, Scallions & Green Olives

Bring a large pot of salted water to a boil. Drop the cauliflower into the boiling water and cook until the florets offer little resistance when pierced with the tip of a knife, 3 to 4 minutes. (Don't let the cauliflower become at all mushy.) With a slotted spoon or a skimmer, remove the cauliflower from the pot and drain it. Return the water to a boil for cooking the pasta. When the cauliflower is cool enough to handle, cut the florets into smaller pieces and set aside. In a large skillet, heat 2 Tbs. of the olive oil over medium-low heat. Add the garlic and scallion whites and cook until fragrant but not browned, about 5 minutes. Add the pepper flakes and anchovies, crushing them with a wooden spoon, and cook for another 1 to 2 minutes. Remove the skillet from the heat while you cook the pasta. Just before the pasta is done, return the skillet to medium-high heat and add the cauliflower and half of the breadcrumbs. Cook, tossing once or twice, until heated through. When the pasta is just tender, reserve 1 cup of pasta cooking water and then drain the pasta, leaving drops of water clinging to it. Add the pasta and 1/2 cup of the reserved pasta cooking water to the skillet, using more or less as needed. Stir in the olives and the scallion greens. Drizzle with the remaining olive oil to taste. Heat gently for a few minutes so that flavors meld. Taste for salt and pepper. Serve warm, passing the remaining breadcrumbs at the table.