Roast Leeks with Thyme and Garlic

Leeks are such a rewarding vegetable and can be given so many imaginative treatments it surprises me that they seem to be joining the ranks of overlooked veg in this country. Perhaps it is the perceived difficulty of getting all the grit out of them that has had this effect. It is actually quite easy: just cross-cut the green tops and fan out the leaves, so that you can rinse away every last bit. This dish is wonderful with any roast but particularly suits fish.