For the spinach lasagna, peel and finely chop the onion and garlic. Clean the mushrooms. Cut mushrooms into slices. Wash spinach, sort and chop coarsely.
Preheat oven to 175 degrees.
Heat oil in a large frying pan and sauté onions, garlic, mushrooms and tomatoes. When onions are translucent, add chopped parsley and oregano. Add spinach and stir well. Season to taste with salt and pepper.
Mix half of the mozarella with the other cheeses in a large bowl. Add the vegetables to the cheese and stir in neatly.
Now layer lasagna sheets alternately with the vegetable and cheese mixture in a baking dish.
Cover with the remaining mozzarella and bake according to the lasagna sheets’ package instructions. Let the spinach lasagna rest for about 5-10 minutes before serving.