Step 1

Preheat oven to 180°C (350°F).

Step 2

Remove the outer leaves from the romanesco and wash thoroughly. Place the whole romanesco stem down in a large oven-proof dish.

Step 3

Whisk together the olive oil, za'atar and garlic powder (if using). Pour and brush this mixture over the romanesco, making sure to get it into all the nooks and crannies.

Step 4

Cover loosely with foil, then roast at 180°C (350°F) for 50-60 minutes. Remove the foil and continue to cook for a further 20-30 minutes until the romanesco is tender when tested with the point of a knife.

Step 5

Serve hot.