Place the milk, butter, flour and bay leaf together in a saucepan, giving it a good season.
Heat over a medium heat, whisking the whole lot continuously until it comes to a simmer point and has thickened. Cook for 5 minutes.
Stir in the parmesan and remove the flyleaf; set aside.
Remove the stalks from the spinach and wash thoroughly.
In a large saucepan put the knob of butter and spinach leaves together, put a lid on and cook for 2-3 minutes on medium heat, making sure the leaves dont burn.
Drain the spinach in a colander and allow to cool. Squeeze all the liquid out of the spinach and chop finely.
In a bowl combine the chopped spinach, ricotta, cream, nutmeg and salt and pepper to taste. Mix well and add the cheddar.
In a small frying pan over a medium heat and add the pine nuts and dry fry for about 1 minute to toast them.
To assemble the lasagna spread a 1/4 of the sauce into the bottom of a ovenproof dish
Add a 1/4 of the spinach mixture, followed by a scattering a pine nuts and 1/4 of the mozzarella. Now place lasagna sheets on top, they may need to be torn to fit the dish.
Repeat the process until all ingredients are layered, finishing with a layer of pasta, the rest of the sauce and the remaining cheese.
Place in the oven and cook for 50-60 minutes or until the top is golden and bubbling.
Remove from the oven and allow to settle for 10 minutes.
Very nice and easy meal. Although a little hard to know how much spinach in grams - i think it put it too much!