OK, here it is:
8 ounces fresh mushrooms, sliced
2 tablespoons butter, melted
1/2 cup dry white wine
1/2 teaspoon dried tarragon
1/4 cup (1/2 stick) butter
1/4 cup flour
1/4 teaspoon nutmeg
Salt to taste
1/4 teaspoon white pepper (I only had black pepper!)
2 cups half and half
2 cups chicken broth
8 ounces uncooked lasagna noodles
5 cups shredded cooked chicken breasts (I poached them, to keep them moist)
12 ounces Swiss cheese, shredded ( I used a little more, and used half Mozzarella)
Saute the mushrooms in 2 tablespoons butter in a large skillet until light brown. Add the wine and tarragon and cook over medium heat until the liquid evaporates.
Melt 1/4 cup butter in a small saucepan. Whisk in the flour, nutmeg, salt and pepper. Cook for 1 to 2 minutes, stirring constantly. Remove from the heat and stir in the half and half and chicken broth gradually. Cook until thickened and smooth, stirring constantly. Stir in the mushrooms.
Cook the noodles using the package directions, rinse with cold water and drain.
Spread a thin layer of the sauce in a greased 9x13 baking dish. Layer the noodles, chicken, sauce and cheese 1/3 at a time in the prepared dish.
Bake, uncovered, at 350 degrees for 40 to 50 minutes or until bubbly. Let stand for 5 minutes before serving.