Preheat oven to 180ºC . Grease and flour 25 cm bundt pan. Sift flour, baking powder and baking soda. Cream butter with 1.5 cups sugar. Beat in yolks, one at a time, mixing well after each addition. Continue beating until light and fluffy. Add dry ingredients to batter alternately with buttermilk mixture. Beat whites until stiff but not dry. Fold into batter. Spoon half of batter into prepared pan. Sprinkle with remaining sugar and then cinnamon. Add remaining batter, spreading evenly. Bake until tester in center comes out clean, about 1 hour. Cool in pan for 20 minutes. Invert cake onto serving platter. Serve warm. From The Cookie Lady's Files ----