Step 1

Preheat oven to 220°C. Heat the oil in a large saucepan over medium heat. Add the chicken and cook, using a wooden spoon to break up any lumps, for 1 minute. Add zucchini and sweet potato, and cook, stirring often, for 4 minutes or until they soften slightly. Stir in pasta sauce and tomato puree. Season with salt and pepper.

Step 2

Use a fork to mash the ricotta, parmesan and nutmeg in a bowl to combine. Spread 1/4 of the chicken sauce over the base of a 6cm-deep, 21 x 33cm (base measurement) ovenproof dish. Top with a layer of pasta sheets, cutting to fit if necessary.

Step 3

Spread 1/3 of the remaining chicken sauce over pasta and then top with pasta. Use damp fingers to spread the ricotta mixture over the pasta. Cover with pasta and then 1/2 the remaining chicken sauce. Top with pasta and the remaining chicken sauce.

Step 4

Cover with foil and bake in preheated oven for 25 minutes. Remove the foil and sprinkle with the cheddar. Bake for a further 5 minutes or until the cheddar melts.