In a large saucepan placed over medium to high heat, spray some Frylight. Add all the vegetables and cook for a couple of minutes, then add the meat and cook until there is no pink bit left.
Add the chopped tomatoes, passata, mixed herbs, salt and pepper. Bring to a simmer and cook over low heat for about 30 minutes.
Meanwhile, make the white sauce. Mix together the eggs, yoghurt, nutmeg, salt and pepper.
Place a thin layer of tomato sauce at the bottom of a large rectangular dish. Place a layer of lasagna, cover with tomato sauce, then add some white sauce. Repeat twice, until all the ingredients are used up, finishing with the white sauce. Top with reduced-fat cheddar and bake for about 30 minutes. Let sit for about 5 to 10 minutes before slicing into six portions.
Serve with a side of salad.