Chicken Tetrazzini

I have made a lot of tetrazzini in my years but this recipe I believe is one of the best.  I really liked the chardonnay in it.  This is NOT for the person on a diet.  We paired it with watermelon.  Figured it would cancel each out for calories - right??

1 stick butter 

1/2 cup flour
2 cups heavy whipping cream
1 (14 oz can) chicken broth
1/3 cup chardonnay
1 Tablespoon chicken granules
1 teaspoon garlic powder
1 teaspoon onion powder
1 teaspoon salt
1 teaspoon pepper
3 cups cooked chicken breasts, shredded
8 ounces spaghetti, cooked and drained
1/2 cup shredded Parmesan cheese
1 small can mushrooms or fresh  mushrooms - to your tasting

2 T butter
1/2 cup panko crumbs
1/4 teaspoon salt

Preheat oven to 325.  Melt 1 stick of butter in a large pot over medium-high heat.   Whisk in the flour until blended and cook for 1 minute, whisking constantly.  Stir in cream, broth, wine, and seasonings and bring to a boil.  Lower the heat and cook for 7-8 minutes or until thick and bubbly, whisking constantly.   Remove from heat and stir in chicken, pasta, mushrooms and cheese.   Spoon mixture into a greased 13x9 baking dish.  Melt 2 tablespoons of butter in a skillet and stir in panko crumbs until they start to brown.  Remove from heat, stir in salt and sprinkle crumb mixture over the top of the chicken mixture.  Bake for 20 minutes.  Let stand 5 to 10 minutes before serving.