Cook noodles according to package directions; drain. In a large skillet, saute mushrooms in 1/4 cup butter for 10-15 minutes or until tender.
Place a third of the noodles in a greased 13-in. x 9-in. baking dish; sprinkle with 1/2 teaspoon salt and 1/4 teaspoon pepper. Layer with 1-1/3 cups cheese and a third of the mushrooms. Repeat layers twice. Dot with remaining butter.
Bake, uncovered, at 350° for 25-30 minutes or until bubbly and cheese is melted. Yield: 8-10 servings.