Autumn and winter vegetables are great for roasting. Be flexible with this dish and vary the ingredients, depending on what looks appealing and seasonally available.
Parmesan cheese is not truly vegetarian, as it contains animal rennet. To make this dish 100% vegetarian, omit the cheese or find a suitable vegetarian substitute made without animal rennet. In supermarkets look for the 'parmesan style hard cheeses' which are suitable for vegetarians.
*You could make this dish with parsnips, carrots, swede or turnip, peeled and cut into chunks, instead of the squash, or throw in some small button onions – whatever takes your fancy. For a special occasion, substitute thickly sliced shiitake mushrooms in place of the chestnut variety.
*Fresh rosemary is an easy herb to grow and is a hardy evergreen, so it can be used year round.