-(finely chopped) Spray a 6-cup fluted tube pan or a 13x9x2-inch baking pan with nonstick coating. (If using a fluted pan, dust with all-purpose flour.) In a mixing bowl combine the sugars, oil, and egg whites. Stir mixture till well blended. Add the all-purpose flour, whole wheat flour, the 2 tablespoons crystallized ginger, baking soda, and nutmeg. Stir mixture just till moistened. (Batter will be thick.) Stir in shredded pears. Pour batter into the prepared pan. Bake in a 350 F oven for 50 to 55 minutes for the tube pan or 25 to 30 minutes for a 13x9x2-inch pan or till a wooden pick inserted near the center comes out clean. (For the tube pan, cool on wire rack 15 minutes before removing cake from pan.) Cool completely. For topping, in a bowl combine yogurt and the 1 teaspoon crystallized ginger. Cover and chill several hours before serving. To serve, dollop each serving wtih the ginger-yogurt topping. Sprinkle with nutmeg, if desired.