Spinach-Leek Lasagna with Mushroom Filling

This is my go-to recipe when I want to impress someone. It is time-consuming to make but always gets raves from everyone.
- Kathy

INGREDIENTS

White Sauce:

2 tablespoons margarine or butter
¼ cup all-purpose flour
¼ teaspoon salt
⅛ teaspoon ground nutmeg
3¼ cups low-fat (1%) milk
⅓ cup grated Parmesan cheese

Spinach-Leek Mixture:

3 medium leeks (about 1 ¼ pounds)
2 tablespoons margarine or butter
½ teaspoon salt
¼ teaspoon coarsely ground black pepper
2 bunches or bags spinach (10 - 12 oz. each), tough stems discarded, coarsely chopped

Mushroom Filling:

1 tablespoon margarine or butter
1 pound mushrooms, cut into ¼” pieces
½ teaspoon salt
2 garlic cloves, crushed with garlic press

8 no-boil lasagna noodles (three-fourths 8-oz package)
2 ounces Fontina cheese, shredded (½ cup)

INSTRUCTIONS

Prepare White Sauce: In 3-quart saucepan, melt butter over medium heat. With wire whisk, stir in flour, salt, and nutmeg, and cook 1 minute. Gradually whisk in milk and cook over medium-high heat, stirring frequently, until sauce boils and thickens. Boil 1 minute, stirring. Whisk in Parmesan; set aside. Makes about 3 cups.

Prepare Spinach-Leek Mixture: Trim off roots and leaf ends from leeks. Discard any tough outer leaves. Cut each leek lengthwise in half, then crosswise into ¼” wide slices. Place leeks in large bowl of cold water; swish leeks around to remove sand. Remove leeks to colander. Repeat process, until all sand is removed. Drain well.

In nonstick 12" skillet, melt 1 tablespoon butter over medium-high heat. Add leeks, salt, and pepper; cook until tender about 8 minutes, stirring. Transfer leeks to large bowl.

In same skillet, melt 1 tablespoon butter; add spinach and cook 8 to 10 minutes, until all liquid evaporates, stirring occasionally. Transfer spinach to bowl with leeks; stir in 1 cup White Sauce.

Prepare Mushroom Filling: In same skillet, melt butter over medium-high heat; add mushrooms and salt, and cook 12 to 14 minutes, until mushrooms are browned, stirring occasionally. Add garlic; cook 1 minute. Add ¼ cup water; cook, stirring, until liquid evaporates. Transfer mushroom mixture to medium bowl; stir in ¾ cup White Sauce.

Assemble lasagna: preheat oven to 350° F. Into 8" x 8" ceramic or glass baking dish, evenly spoon 1/2 cup White Sauce. Arrange 2 noodles over sauce, making sure noodles do not touch sides of dish (they will expand), then top with half of Spinach-Leek Mixture, then 2 noodles. Spoon Mushroom Filling over noodles; top with half of Fontina Cheese, Spinach-Leek Mixture, 2 noodles, remaining White Sauce, and Fontina cheese.

Cover lasagna with foil and bake 40 minutes or until hot and bubbly. Let lasagna stand 10 minutes for easier serving. Makes 6 servings.