Preheat oven at 375. Prepare a baking sheet with cooking spray. In am mixing bowl, combine flour, sugar, baking powder, baking soda and salt. In a mixing bowl, combine margarine, egg white, sour cream, lemon extract, lemon peel. Mix dry ingredients with wet ingredients just until moistened. Chill overnight. Divide dough into 4 parts. Refrigerate unused portions until ready to roll out. On floured surface roll dough, one part at a time, 1/4" thick, using a 2" cookie cutter. Place cookies on a prepared baking sheet 2" apart. Lightly brush cookies with lemon juice. Bake for 10 to 12 minutes until golden brown. ----