Cook the pasta as directed on package, but undercook it by a minute or two. Drain, then rinse with cold water and drain again. Toss with a teaspoon of olive or vegetable oil. Refrigerate in tightly covered container or resealable food-storage plastic bag up to 5 days. When making the pilaf, add pasta to the skillet after cooking mushrooms and green onions, and heat through. Then stir in the remaining ingredients and heat through.