Step 1 : Preheat the oven to 32

Step 2 : In a large bowl, whisk together the flour, 3/4 cup granulated sugar, the pumpkin pie spice, baking powder and salt. In a medium bowl, combine the egg yolks and pumpkin puree. Stir the pumpkin mixture into the flour mixture until smooth.Using an electric mixer with a whisk attachment, whip the remaining 9 egg whites at medium speed until foamy, about 2 minutes. With the machine on, gradually whisk in the remaining 1/2 cup granulated sugar; increase the speed to high and beat until stiff but still moist, 1 to 2 minutes.

Step 3 : Add one-quarter of the egg white mixture to the pumpkin batter, folding with a rubber spatula just until no streaks remain. Fold in the remaining egg white mixture in the same manner.

Step 4 : Pour the batter into a 10-inch tube pan with a removable bottom and bake until springy to the touch and a cake tester inserted in the center comes out clean, 55 minutes.

Step 5 : Let cool in the cake pan for 5 minutes, then invert the pan onto a narrow-necked bottle and let hang upside down until completely cool, about 1 1/2 hours.

Step 6 : Place the cake right side up and remove the pan. To serve, dust the cake with the confectioners sugar.