Mushroom Lasagna

1. White Sauce: In 3-quart saucepan, melt butter over medium-low heat. Add flour all at once and stir until blended; cook 2 minutes. Slowly add milk, whisking until smooth; sauce at first will become thick, then it will gradually loosen up. Increase heat to medium, stirring constantly, until sauce comes to a simmer. Stir in salt, pepper and nutmeg; simmer 4 minutes more. Remove from heat. (Sauce can be prepared ahead. Pour into bowl; place piece of plastic wrap directly on surface and refrigerate for up to 2 days. Let come to room temperature before using.)

2. Mushroom Filling: In large skillet, melt butter over medium-high heat. Add onion; cook, stirring occasionally, until softened, 5 minutes. Stir in mushrooms, salt and pepper; cook, stirring frequently, until all the liquid evaporates and mushrooms are tender, about 12 minutes. Remove from heat. Stir in spinach and carrots.

3. Heat oven to 375 degrees F.

4. Lasagna: Spread 1 cup white sauce over bottom of 13 x 9 x 2-inch lasagna pan. Set aside 1 cup white sauce. Stir remaining white sauce into mushroom mixture.

5. Arrange 4 lasagna sheets on top of sauce. Spread with half the mushroom mixture. Sprinkle with 1/2 cup cheese. Repeat layering, ending with sheets. Spread 1 cup sauce over top, spreading to cover pasta completely. Cover with foil.

6. Bake in 375 degree F oven 45 minutes. Uncover; sprinkle with remaining 1/2 cup cheese. Bake 15 minutes more or until browned and bubbling around edges. (If desired, run lasagna under broiler 2 minutes to brown and crisp top.) Let stand 10 minutes before serving. Cut into rectangles to serve. Makes 12 servings.