Combine brown sugar, melted margarine or butter, and cornstarch in a small bowl. Drain pears, reserving 3 tablespoons syrup. Stir reserved syrup into brown sugar mixture. Pour mixture into a 10x2-inch round baking pan or a 9x9x2-inch baking pan.
Cut pears into fans by making three or four lengthwise cuts from the bottom of the pear to 1/2 inch from the top. Arrange pears, small ends in the center and rounded sides down, on syrup in pan.
Combine flour, pumpkin pie spice, baking soda, and baking powder in a small bowl; set aside. In another mixing bowl beat egg whites with an electric mixer on medium speed until soft peaks form. Gradually add sugar, beating until stiff peaks form. Using low speed, beat in pumpkin and oil. Fold flour mixture into pumpkin mixture just until moistened. Carefully spoon over pears. Spread mixture evenly with back of spoon.
Bake in a 350 degree F oven for 40 to 45 minutes or until a toothpick inserted near center comes out clean. Cool about 5 minutes. Loosen from side of pan; invert onto serving plate. Serve warm. Makes 10 to 12 servings.