1 pound bucatini
1/4 cup extra-virgin olive oil, plus more for drizzling
1 sprig oregano, plus 1 tablespoon lightly packed fresh leaves
1/4 teaspoon red-pepper flakes, plus more for serving
2 1/2 teaspoons coarse salt
1 teaspoon finely grated lemon zest and 2 tablespoons fresh lemon juice, plus wedges for serving
4 cups finely chopped cauliflower florets (from 1 head)
3 tablespoons capers, preferably salt-packed, rinsed and drained
1/2 cup finely grated Parmesan (1 1/2 ounces), plus more for serving
Heat broiler with rack 8 inches from heating element.
Combine pasta, 5 cups water, 2 tablespoons oil, oregano sprig, pepper flakes, and 2 teaspoons salt in a large, straight-sided ovenproof skillet. Bring to a boil over medium-high heat; continue cooking, stirring occasionally, until sauce is mostly reduced and pasta is al dente, about 8 minutes. Remove from heat; stir in lemon zest and juice.
In a bowl, toss cauliflower with remaining 2 tablespoons oil and 1/2 teaspoon salt, capers, Parmesan, and oregano leaves. Sprinkle over pasta in skillet.
Broil until cauliflower is golden in spots and pasta is heated through, about 5 minutes. Toss to combine. Serve with more cheese and pepper flakes, a drizzle of oil, and lemon wedges.
Lodge Color Enameled Cast Iron Skillet, Island Spice Red, 11-inch