Combine 2 cups flour, 1/2 cup powdered sugar and 1 cup butter in food processor. Pulse until well combined. Spread into an ungreased 15X10 pan. Bake at 350 degrees for 14 to 16 minutes, or until set. Check crust after 10 minutes of baking. If it is puffing up, prick holes into it with a fork. Remove from oven. Meanwhile, combine cream cheese, 1/2 cup powdered sugar, 2 tablespoons flour, 2 eggs and 1 teaspoon vanilla in a large mixer bowl. Stir on low speed to combine. Increase speed to medium, and beat for 2 minutes, or until it is smooth and creamy. Pour over crust. Bake at 350 degrees for 6 to 7 minutes, or until filling is slightly set. Remove from oven. Meanwhile, combine 4 eggs, 2 cups sugar, 1/4 cup flour and lemon peel in large mixer bowl. Stir on low speed to combine. Gradually stir in lemon juice and mix until will blended. Pour over cream cheese layer. Bake at 350 degrees for 14 to 16 minutes, or until filling is set. Note: filling may puff up during baking and then fall when removed from the oven. Cool completely in pan. Sprinkle with powdered sugar before serving. Cut into 48 bars.