Club-shaped butternut squash are widely available and make any dish look attractive and taste superb. Their glorious, sweet, orange flesh is rich in beta-carotene, as well as containing vitamins C and E.
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.
Use a pumpkin instead of butternut squash. You'll need about 700g prepared flesh. * Replace half the butternut squash with diced courgettes and green peppers.
The tart can be made ahead, then gently warmed before serving.