This is a take from a recipe I found some years back for an Alaskan Halibut Lasagna. I used chicken which I had on hand at the time and now always make it this way. I haven't tried it with Halibut but please feel free to give it a try. I would love to know how it turned out! This is very rich but full of flavor.
In a large skillet over medium heat, melt 2 tablespoons butter. Add chicken. Cook until no longer pink. Add garlic; cook 1 minute longer. Remove and set aside.
Add the remaining butter to the skillet. Stir in flour and salt until smooth; cook and stir until golden brown. Gradually add broth and cream. Bring to a boil; cook and stir for 2 minutes or until thickened.
In a greased 13-in. x 9-in. baking dish, layer half of the noodles, halibut, white sauce and cheese. Repeat layers. Cover and bake at 350° for 20 minutes. Uncover; bake 20 minutes longer or until bubbly. Let stand 15 minutes before serving. Sprinkle with parsley if desired.