Preheat oven to 375°.
Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and next 7 ingredients (flour through cloves) in a bowl. Combine buttermilk, egg substitute, 1/4 cup butter, and molasses in a bowl. Add to flour mixture, stirring until smooth.
Melt 1 tablespoon butter in a 9-inch cast-iron skillet. Stir in 1/3 cup brown sugar, and cook over medium heat 1 minute. Remove from heat; sprinkle with walnuts.
Place pear slices in the bottom of skillet. Pour batter over pears. Bake at 375° for 30 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes on a wire rack; invert cake onto a serving plate. Serve warm or at room temperature.