Preheat oven to 350°F. Prepare rice mix according to package directions.
Remove mushroom stems; set caps aside. Finely chop mushroom stems. In medium bowl, combine cooked rice, mushrooms stems, Parmesan cheese and pimentos. Fill mushrooms with rice mixture, mounding on top.
Place mushrooms on a foil lined baking sheet. Bake 20 minutes or until mushrooms are tender. Garnish with chives.
Make it a side dish ... prepare as mentioned and use as a stuffing for large portobello mushrooms.