Choose a grilling pan to prepare the vegetables.
Grill all the vegetables on both sides, ensuring they are thoroughly cooked, using the cooking spray to ensure they do not stick to the pan. It is important that the vegetable slices are not too thick, so while they cook they can release the excess moisture; this will ensure the lasagna doesn’t end being too sloppy at the end.
Once all the vegetables are ready, set them aside to cool down.
Prepare the tomato sauce by warming up the olive oil in a saucepan; once the oil is warm, add the garlic, onion, basil leaves, salt, and pepper and mix well. Allow the onion and garlic to cook on a medium-low flame until tender and the smell of the rawness of the garlic has gone.
Once the onion and garlic are ready, add the chopped tomato and passata and mix well; bring them to the boil then reduce the flame to low, put a lid on the saucepan and allow the sauce to simmer for 15 minutes until the tomato sauces are cooked.
Once the tomato sauce is ready, should it be too acidic, you can correct this by adding the caster sugar; should it not be too acidic, then just skip this step.
Prepare the cheese on the side by grating 30g of Parmesan cheese and thinly slicing the mozzarella.
Preheat the FAN oven to 180 degrees Celsius, 400 Fahrenheit, 200 degrees Celsius Static Oven or Gas Mark 6.