Clean and gut. Rub in some oil, salt, pepper and lemon juice. If you've got fresh herbs you can stuff them into the fish or, in this case, grind them in a mortar and pestle with some oil and juice. Lay in a tray on top of some roughly chopped veg. Pour over some oil and mix in.
Cook covered in the oven for half an hour. Goes great with roast potatoes or rice.