Preheat oven to 180°. Spray base of pan with nonstick cooking spray. In medium bowl, with wire whisk, combine flour, baking powder and baking soda. In large bowl, with electric mixer on medium speed, beat eggs with sugar until light and fluffy. Beat in Hellmann’s Mayonnaise, sour cream, grated lemon peel and vanilla and beat well. Fold in the flour mixture just until blended. Spoon the batter into prepared pan. Bake for 35 minutes or until toothpick inserted in center comes out clean. On wire rack, cool for 15 minutes. Remove from the pan and cool completely. Sprinkle, if desired, with icing sugar and serve.