In a large mixing bowl, cream the confectioners sugar and butter until fluffy. Beat in the egg, lemon peel, lemon extract, and vanilla extract.
In a seperate bowl, combine the flour, baking powder, and salt. Add dry ingredients to the wet ingredients, mixing just until combined. With well floured hands, roll the dough into a 1 1/2 inch wide log. Wrap the log in plastic wrap and refridgerate 30 minutes.
Preheat oven to 350. Slice the dough into 1/4 inch thick slices; place the rounds 1 inch apart on an ungreased baking sheet. Bake 9 to 11 minutes. Cool for 1 minute on the baking sheet, then transfer the cookies to wire rack to cool completely.
To make glaze, melt the chocolate in a double boiler over hot not boiling water. Stir until the chocolate is smooth. Add the melted butter and continue stirring until well blended.
Line the baking sheets with waxed paper and coat lightly with non-stick cooking spray. Holding a cookie vertically, dip it halfway into the melted chocolate mixture. Place the cookie on one of the prepared baking sheets. Repeat with rest of the cookies. Transfer the baking sheets to a cool place and allow the chocolate to set, about 45 minutes to 1 hour. Store tightly covered with waxed paper seperating layers.