Preheat oven to 350°F. Spray 8x8 inch baking pan with non-stick spray.
In a food processor combine ¾ cup flour, 3 tbsp granulated sugar and the vanilla seeds. Pulse in the butter until crumbly.
Pat mixture onto the bottom of the prepared pan. Bake for 15 minutes.
In a medium mixing bowl, combine egg and egg white. Beat with an electric mixer on medium speed until frothy.
Add 2/3 cup granulated sugar, 2 tbsp flour, lemon peel, lemon juice, water, and baking powder.
Beat on medium speed for 3 minutes or until slightly thickened. Pour mixture over baked layer in pan. Bake for 20 to 25 minutes more or until edges are light brown and center is set.