Preheat the oven to 400 degrees Fahrenheit and arrange the cauliflower florets across a shallow oven tray.
Step 2
Finely chop the rosemary and crush the garlic. Dot the butter over the cauliflower and sprinkle over the chopped rosemary, garlic, lemon zest, salt and pepper.
Step 3
Transfer to the oven and roast for 18-20 minutes, turning halfway through, until fork tender and golden at the edges. Serve hot.