1. Combine chicken, 1 cup water, garlic and bay leaf in large
2. Cover and simmer just until chicken is cooked
through, turning once, about 15 minutes.
3. Transfer chicken to
plate; cool. Shred chicken. Pour cooking liquid into measuring
cup, adding more water to measure 1 cup if necessary. Reserve
4. Whisk flour and cornstarch in heavy large
saucepan. Add 1 cup milk; whisk until smooth. Stir in 1 cup
milk, tarragon, salt, nutmeg and reserved 1 cup chicken cooking
5. Stir over medium heat until mixture thickens and boils,
about 5 minutes. Add wine; stir until mixture is very thick,
about 2 minutes longer. Remove from heat.
6. Stir in shredded
chicken and spinach. (Can be made 1 day ahead. Cover and chill.
7. Reheat over medium-low heat, stirring frequently, before
continuing.) Preheat oven to 400 degrees.
8. Oil 11 x 7 x 2-inch
glass baking dish. Cook fettuccine in large pot of boiling
salted water until just tender but still firm to bite. Drain.
Return to pot.
9. Add mushrooms and chicken mixture; toss. Season
with salt and pepper.
10. Transfer to prepared baking dish. Heat
oil in small nonstick skillet over medium-high heat.
breadcrumbs; stir 1 minute. Sprinkle over casserole.
12. Bake until
casserole bubbles and breadcrumbs are golden, about 20 minutes.
Let stand 10 minutes. Sprinkle with Parmesan and serve.