Coarsely chop parsnips. In heavy saucepan heat butter and water. Place chopped parsnips, cover, and steam until soft and water is absorbed. Remove from heat. In food processor puree until smooth. Return puree to pan, cover and keep warm until ready to serve. To make cherry sauce, in heavy saucepan caramelize sugar until deep golden brown. Remove from heat and add vinegar. Return to heat, add ginger and cook for about 5 minutes. Remove from pan and set aside. Heat dry saucepan until hot. Brown foie gras on one side. Turn over and cook for about 30 seconds. Serve topped with parsnip puree and cherry sauce.