1. Trim away the outer leaves, retaining some of the inner tender leaves; hollow out the stem to a depth of 2 cm, then wash in cold salted water.
2. Place into boiling salted water containing the lemon juice, reboil, skim and simmer for 8 minutes, keeping the cauliflower firm.
3. Drain well, sprinkle with 50 g grated Parmesan cheese and 50 g melted butter and glaze under a salamander grill.