In a large skillet over medium heat, melt 2 tablespoons butter.
Add halibut, garlic and thyme, Cook until fish flakes easily with a fork, about 10 minutes.
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 x 9 x 2 inch baking dish, layer half of the noodles, halibut, white sauce and cheese. Repeat layers.
Cover and bake at 350 degrees for 20 minutes, then uncover and bake 20 minutes longer or until bubbly.
Let stand 15 minutes before serving. Sprinkle with parsley if desired. Yield: 8 servings.