Preheat oven to 200C/180C fan-forced. Grease a 6cm-deep, 20cm x 30cm baking dish.
Combine spinach, ricotta, nutmeg, egg, basil and 1/2 cup parmesan in a bowl. Season with salt and pepper to taste. Stir.
In a large jug, place soup and stock. Over the base of the prepared dish, place 2 lasagne sheets breaking to fit, if necessary. Over the lasagne sheets, spoon one-third of ricotta mixture, spreading to cover. Top with 1/3 cup mozzarella. Drizzle with 1/2 cup pumpkin soup mixture. Repeat layering process twice, finishing with lasagne sheets. Pour over remaining pumpkin soup mixture. Top with remaining mozzarella and parmesan.
Cover dish with foil. Bake for 30 minutes. Uncover. Bake for another 20 minutes or until golden and tender. Rest for 10 minutes. Serve with extra basil leaves.
