Brush 10-inch cast iron skillet or 8x8-inch glass baking dish with butter.
To make gingerbread: Whisk flours, ginger, cinnamon, baking powder, baking soda and salt in medium bowl. Beat egg, sugar and molasses with mixer for 3 minutes. add applesauce and oil, and beat until blended. Fold in flour mixture and yogurt.
To make pear topping: Press brown sugar over bottom of prepared skillet. Sprinkle with nuts. Arrange pear slices in circles over nuts. Pour batter over pears.
Bake 35 - 40 minutes or until toothpick inserted in center comes out clean. Loosen edges with knife. Invert cake onto platter.