WHITE SAUCE:
4 tbs. unsalted butter
1/2 cup flour
6 cups 1% low-fat milk
1 tsp. salt
1/2 tsp. black pepper
1/4 tsp. ground nutmeg
MUSHROOM FILLING:
2 tbs. unsalted butter
1 large onion, finely chopped
1 1/2 lbs. white button mushrooms (or portabellos) coarsely chopped
1/2 tsp. salt
1/4 tsp. black pepper
10 oz. frozen chopped spinach, thawed and squeezed dry
2 medium sized carrots, grated
LASAGNA:
12 sheets oven ready, no-boil lasagna
1 1/2 cups Grana Padano or Parmigiano-Reggiano cheese, freshly grated
WHITE SAUCE: Melt the butter in a 3 quart saucepan over medium-low heat. Add the flour all at once and stir until blended; cook for 2 minutes. Slowly add the milk, whisking until smooth. Increase heat to medium, stirring constantly, until the sauce begins to simmer. Stir
in the salt, pepper and nutmeg. Simmer 4 minutes more. Remove from heat and set aside.
MUSHROOM FILLING: Melt the 2 tbs. butter over medium heat in a large skillet. Add the onion and cook until softened, about 5 minutes. Add the mushrooms, salt and pepper; cook, stirring frequently, until all the liquid evaporates and the mushrooms are tender, about 12 minutes. Remove from heat and stir in the spinach and carrots. Pre-heat the oven to 375 degrees F.
LASAGNA: Spread 1 cup white sauce over the bottom of a 13 X 9 X 2 inch lasagna pan. Reserve 1 cup of white sauce. Stir the remaining white sauce into the mushroom mixture. Arrange 4 lasagna sheets on top of the sauce in the lasagna pan. Spread with half the mushroom mixture. Sprinkle with 1/2 cup of grated cheese. Repeat layering, ending with lasagna sheets. Spread the reserved cup of white sauce over the top, spreading to cover the pasta completely. Cover the pan with foil. Bake at 375 degrees F. for 45 minutes. Uncover and sprinkle with the remaining 1/2 cup grated cheese. Bake for 15 minutes more, or until browned and bubbling around the edges. Let stand 10 minutes before serving. Cut into 9 pieces and serve. This recipe makes 9 servings, 8 points per serving.