DIRECTIONS

In a small mixing bowl, cream butter and sugar until light and fluffy. Beat in extract. Combine flour and salt; gradually add to the creamed mixture and mix well.
    Roll teaspoonfuls into balls. Place 1 in. apart on ungreased baking sheets; flatten slightly. Bake at 350° for 10-12 minutes or until lightly browned.
    Meanwhile, for filling, combine the egg, sugar, lemon juice, peel and butter in a heavy saucepan. Cook and stir until thickened and a thermometer reads 160°, about 20 minutes. Refrigerate for 1 hour or until completely cooled.
    Spread lemon filling on the bottoms of half of the cookies; top with remaining cookies and roll in additional confectioners' sugar. Store in the refrigerator. Yield: about 4 dozen.