Crank your oven to 190°C (170°C fan-forced/375°F) and grease a baking dish with olive oil or spray.
Warm the olive oil over medium heat in a large saucepan. Add the onion and sauté for about 5 minutes until golden.
Add the garlic to the onions and stir for about a minute.
Add pumpkin cubes, lentils, vegetable stock, and most of the passata to the saucepan. Mix well.
Bring to a gentle simmer, cover, and cook for 20 minutes until the pumpkin is soft.
Cool the mixture for 10 minutes, then refrigerate until completely cold.
In a bowl, mash ricotta with a fork until smooth, add nutmeg, salt, and pepper.
Line the dish with lasagne sheets and spread half the pumpkin-lentil mixture over them.
Add another layer of lasagne sheets, spread the ricotta, and top with spinach.
Add another layer of pasta sheets, then remaining pumpkin-lentil mixture.
Top with the final layer of pasta sheets, pour remaining passata, and sprinkle cheddar on top.
Bake for 45 minutes until golden. Let it rest for 10-15 minutes before serving.
Serve with rocket leaves on top or on the side.
