Clean fresh mushrooms, if using. If using dried mushrooms, place in a medium bowl and pour boiling water over to cover; let stand 30 minutes. Rinse and drain well; discard tough stems, if present. Thinly slice mushrooms and set aside. (You should have about 3 cups if using fresh mushrooms and about 1-1/2 cups if using dried.)
Prepare the pasta according to the package directions.
Meanwhile, in a large skillet heat butter or margarine and oil over medium heat. Cook mushrooms, pepper, and salt, uncovered, for 8 minutes or until tender, stirring occasionally. Remove from heat; stir in herbs, if desired. Let stand 3 minutes. Drain pasta; toss with mushroom mixture. Serve at once. Makes 4 servings.