In a medium bowl combine flour, confectioners' sugar and lavender; cut in butter until crumbly. Press into an ungreased 13 x 9 x 2 inch baking pan.
Bake at 350º for 20 to 30 minutes or until lightly browned.
For filling: In a large mixing bowl, beat eggs until frothy. Stir in lemon juice and peel. Combine the sugar, flour, and baking powder. Stir into the egg mixture. Pour over crust. Sprinkle lavender over top.* Bake for 25 minutes or until set. Cool on a wire rack.
Cut into bars and sprinkle with confectioners' sugar if desired.