Mix flour, butter and powdered sugar. Press in ungreased square pan, 8x8x2 or 9x9x2 inches, building up 1/2 inch edges.
Bake crust 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 center.
Cool, dust with confectioners sugar. Cut into about 1 1/2 inch squares.