1. To prepare the vegetable sauce, finely chop onions and garlic and saute in olive oil.
2. Peel and finely dice the carrots, slice mushrooms and zucchini, dice pepper and add them to the onions. Cook for a few minutes before adding tomatoes and herbs. Simmer until vegetables are softened and season well.
3. For the bechamel sauce, melt the butter in a sauce pan and stir in flour. When it turns golden, gradually whisk in the milk - to prevent lumps, add milk a little at a time and stir vigorously until smooth before adding the remaining milk. Simmer for 10min and season with salt and pepper.
4. In a large baking dish, layer vegetable sauce, bechamel and lasagna sheets. Top with mozzarella and parmesan.
5. Bake at 160°C until the cheese is starting to brown, around 30-45min.