Preheat oven to moderate, 80°C. Lightly spray an 8 cup baking dish with oil. Preheat a char-grill on high.
Char-grill capsicum, skin-side up for 10 minutes until it blisters and blackens. Cover capsicum pieces in plastic wrap for 10 minutes. Peel away skin. Cut flesh into strips.
Char-grill kumara and eggplant for 2-3 minutes each side, until tender. Set aside until required.
Meanwhile, melt spread in a medium saucepan on high. Stir in flour and cook for 1 minute. Remove from heat. Gradually whisk in milk until smooth. Return to heat and cook, stirring, for 5-6 minutes, until sauce boils and thickens. Season to taste. Remove from heat and stir cheese through.
Place a lasagne sheet on the base of prepared dish, trimming to fit. Spread over half pasta sauce. Layer with half vegetables.
Cover with a second lasagne sheet, remaining pasta sauce and vegetables. Top with a final lasagne sheet. Spread over white sauce.
Cover loosely with foil and bake for 25 minutes. Remove foil and bake, uncovered, for a further 15-20 minutes until golden. Set aside 5 minutes before serving topped with fresh basil leaves.
Leftover lasagne sheets can be frozen for up to 3 months. Wrap tightly in plastic wrap to prevent freezer burn.