In a bowl, cream butter, sugar and egg until well blended. Add lemon juice and zest. Combine flour, baking soda, cream of tartar and salt; stir into creamed mixture. Add almonds. Cover and refrigerate the dough for at least 1 hour or overnight.
Roll into 1-in. balls. Place on ungreased baking sheet. Bake at 350° for 10-12 minutes or until bottoms are lightly browned (cookies will not brown on top).
Remove immediately to wire racks; cool for 5 minutes, then roll in confectioners' sugar.