Cook lasagna noodles and drain. Cool under cold running water; drain
again and set aside. Preheat oven to 350°F. In a large saucepan, cook
spinach over medium-high heat, stirring frequently until leaves are
limp 2 to 3 minutes. Drain spinach in a colander and press excess
water out with the back of a wooden spoon. When cool enough to
handle, squeeze dry. Turn spinach out onto a cutting surface and chop
fine.
In a large bowl, combine spinach, ricotta, egg yolks, 3/4 cup
Parmesan cheese, salt, pepper, and nutmeg. Mix with a wooden spoon
until well blended. In a greased 13x9" baking dish, alternately layer
spinach pasta with spinach-ricotta mixture and mozzarella, making a
total four layers. Cover with foil and bake 25 minutes. Uncover and
bake 10 minutes longer, or until tomato sauce and remaining Parmesan
cheese on the side.
