Creamy Cauliflower Pasta With Pecorino Bread Crumbs

Kosher salt and black pepper

rigatoni, ziti or campanelle

olive oil

fresh coarse or panko bread crumbs

finely grated pecorino cheese, plus more for serving

large shallot, finely chopped

medium head cauliflower (about 2 pounds), outer leaves and stem removed, sliced about 1/2-inch thick (it’s O.K. if it crumbles)

heavy cream

finely grated lemon zest, plus more for serving

finely chopped chives

Red-pepper flakes (optional)