1 large head cauliflower (about 2 pounds), stems trimmed, cut into florets
3 tablespoons capers, preferably salt-packed, rinsed and drained
3 tablespoons extra-virgin olive oil, plus more for drizzling
1 1/2 teaspoons small fresh marjoram or oregano leaves (or chopped if large)
1 tablespoon red-wine vinegar
1 teaspoon coarse-grained mustard
Preheat oven to 400 degrees. Place cauliflower and capers on a rimmed baking sheet. Drizzle with 3 tablespoons oil, and toss to combine; season with salt. Spread in a single layer, and roast, stirring occasionally, until cauliflower is golden brown and tender, 30 to 40 minutes. Toss with herbs, vinegar, and mustard. Serve warm or at room temperature, drizzled with oil.