1. Wash and pare turnips and potatoes. Cut into small cubes.
2. Place turnips and potatoes in a deep 3-quart non-metallic casserole.
3. Add water to cover vegetables.
4. Heat, covered, in Microwave Oven 15 to 18 (20 to 23) minutes or until vegetables are fork-tender. Drain excess water.
5. With a potato masher or fork, mash turnips and potatoes until almost smooth.
6. With a rotary beater or electric mixer beat vegetables, butter, salt, pepper, and nutmeg until fluffy.
7. Stir in heavy cream gradually until desired consistency is reached.
8. If desired, stir in parsley.