Season: Best from October to March
The dense, sweet-tasting, orange-fleshed sweet potato is a dramatically different starchy vegetable to the potato. It is, in truth, no relation to the potato at all, though it can be baked, roasted or mashed. It is a variety of yam, and usually the best – those huge white or yellow-fleshed yams can be insipid and rather waxy (an acquired taste is the polite expression).
All these vegetables tend to be well travelled and their exteriors get a bit leathery in the process, so it is best to take the skin off with a peeler, the exception being the smallest, perkiest sweet potatoes, which can be baked in their jackets.
Filled with wintry root veg and a cheesy sauce, with a parmesan pastry, this pie is a real treat! Replace the lard with vegetable fat if making this for vegetarians.
Roasting vegetables is a great way of maximising their nutritional benefit as the vitamins don't leach out into the cooking water - and they're full of flavour and texture. This recipe uses all those wonderful root veg in one go.