Preheat the oven to 200°C, fan oven 180°C, gas mark 6. Put the butternut squash or sweet potatoes, courgette, red onion and pepper into a large roasting tin and add the olive oil. Season and toss to coat. Roast for 25 minutes, until tender.
Add the cherry tomatoes and chilli (if using), then stir in the pasta sauce.
Tip half the vegetable mixture into a large rectangular baking dish, measuring about 25 x 20cm. Arrange 4 lasagne sheets on top. Repeat the layers.
To make the cheese sauce, put the milk, flour and butter into a saucepan. Heat, whisking constantly with a wire whisk until the sauce boils and thickens. Remove from the heat and add half the cheese. Stir, so that the heat of the sauce melts the cheese - there’s no need to return it to the hob. Season.
Pour the cheese sauce over the lasagne and sprinkle the remaining cheese over the top. Bake for 30-35 minutes, until cooked and golden brown. Allow to stand for a few minutes, then serve.
*All information included in this recipe has been provided by Dairy Crest.