Heat over to 350 degrees. Mix flour, butter and powdered sugar. Press in un-greased square pan, building up 1/2 inch edges.
Bake the crust for 20 minutes.
Beat granulated sugar, lemon peel, lemon juice, baking powder, salt and eggs with electric mixer on high speed about 3 minutes or until light and fluffy. Pour over hot crust.
Bake 25 to 30 minutes or until no indentation remains when touched lightly in the center. Cool.
Top with Fresh Whipped Cream, Cool Whip or powdered sugar.
Use fresh or candy lemon sliced for garnish.