As you can see from the picture above, it didn't come out very lasagne-shaped! Tasty though... and served with home-made focaccia.
Mushroom & parmesan bechamel:
For the bechamel, mix the milk and the reserved mushroom stock together in a large saucepan with the onion and bay leaves. Cook over a medium heat for 4 minutes, but do not let it boil. Meanwhile, in a medium pan on a low heat, melt the butter and then add the flour. Keep stirring the mixture for several minutes to cook the flour, which makes a roux. When the milk mixture is just coming to the boil, remove the onion and bay leaves. Whisk the roux into the milk. Keep whisking over the heat until it thickens. Add 60g of parmesan and season to taste with sea salt and black pepper.
Preheat the oven to 180. Heat a large frying pan on a medium heat and add the olive oil and butter. When they have melted together, add the onion, garlic, leek and fresh and wild mushrooms and saute for 5 minutes or so. Add the spinach and continue stirring until it has wilted down. Season to taste, then add the mushroom bechamel to the vegetable mixture and stir.
Line the bottom of a 2 litre ovenproof dish with dried lasagne sheets. Cover with a layer of the bechamel-veg mix. Top with a layer of lasagne sheets, then with a second layer of the leek and mushroom mixture. Sprinkle over the grated parmesan, top with torn baby mozarella then place in the oven to cook for 35-40 minutes, or until golden brown.