Rinse the cauliflower, remove the leaves and cut off the bottom of the stalk so that it sits flat.
Mix the butter, garlic and spices together and season with salt and freshly ground black pepper.
Rub the cauliflower thoroughly all over with the butter mixture, then place it in an ovenproof dish. Cover loosely with foil.
Roast in a preheated conventional oven (top and bottom heat) at 200°C for about 1 hour. Check whether it is tender after 45 minutes – the cooking time depends on the size of the cauliflower.
Remove the foil and roast for a further 15-20 minutes, until golden and appetising. Baste it with a little of the butter from the bottom of the dish if you like.