Chicken, Spinach & Mushroom Lasagna

3 cups unsalted chicken stock
1 1/2 pounds boneless skinless chicken breasts
2 1/2 Tbsp olive oil
2 Tbsp butter
1 1/2 cups chopped onion
3 Tbsp minced garlic
1 1/2 tsp salt
1/2 tsp chopped fresh thyme
1/2 tsp crushed red pepper
10 oz sliced mushrooms
16 oz fresh spinach
1 1/2 cups milk
1/2 cup all purpose flour
1/4 tsp ground nutmeg
2 oz grated parmesan
12 no boil lasagna noodles
5 oz shredded mozzarella cheese

Bring stock to a boil.  Add chicken; reduce heat and simmer 18-20 minutes or until chicken is done.  Remove chicken from pan; reserve stock.  When cool enough to handle, shred with 2 forks.  Heat a large skillet over over medium high heat.  Add oil and 1 Tbsp butter; swirl to coat.  Add chopped onion, garlic, 1/2 tsp salt, thyme, pepper and mushrooms; saute 8 minutes.  Stir in spinach, a little at a time, allowing time for each addition to wilt before adding more.  Remove pan from heat; stir in chicken.  Preheat oven to 375.  Coat 13x9 pan with non stick cooking spray.  Combine milk, flour and nutmeg, stirring with a whisk until smooth.  Bring reserved stock to a boil over medium high heat.  Add 1 Tbsp butter to stock.  Gradually add milk mixture to stock, stirring constantly with a whisk.  Stir in remaining 1 tsp salt.  Cook 5 minutes or until thickened, stirring occasionally.  Remove pan from heat; stir in Parmesan cheese.  Pour 3/4 cup sauce into bottom of baking pan.  Top with 4 noodles, 1 1/2 cups chicken mixture, 1 1/2 cups sauce, and 2 oz Mozzarella making sure noodles are covered with sauce.  Repeat layers, ending with noodles, sauce and mozzarella.  Cover loosely with foil.  Bake at 375 for 30 minutes.  Uncover and bake at 375 for 15 minutes or until browned and bubbly.  Let stand 5 minutes before serving. 

Serves 12