Preheat oven to 200°C/400°F. Line three oven trays with baking paper.
Place pumpkin, zucchini and cauliflower on separate oven trays. Drizzle with 1½ tablespoons of the oil; season with salt.
Roast pumpkin for 10 minutes. Add zucchini and cauliflower; roast for a further 30 minutes or until vegetables are tender. Reserve four slices of zucchini for the top. Reduce oven to 180°C/350°F.
Heat remaining oil in a large deep frying pan over medium heat; cook onion, celery and carrot, stirring, for 10 minutes or until soft. Add wine; bring to the boil. Boil for 5 minutes or until most of the wine is evaporated.
Stir in tomatoes, herbs, capsicum and 1 cup (250ml) water; bring to the boil. Reduce heat to low; cook, covered, for 20 minutes or until thickened slightly. Season to taste.
Process cauliflower until smooth. Transfer to a medium bowl; stir in ricotta, milk and ¾ cup of the parmesan. Season.
Spoon 2 tablespoons of the tomato mixture over base of a 20cm x 30cm (8in x 12in) ovenproof dish. Top with a layer of lasagne sheets, then a layer of pumpkin, zucchini and cauliflower mixture. Repeat with remaining ingredients, finishing with a layer of cauliflower mixture then reserved zucchini. Sprinkle with remaining parmesan.
Bake for 45 minutes or until lasagne sheets are tender. Top with extra basil leaves, if you like; serve.