Prheat the oven to 350F.  In a large bowl, cream the shortening and sugar until light and creamy; beat in the eggs.  Add the flour, baking powder, and vanilla, blending well.  Stir in all of the melted chocolate and the milk, mixing well.  Drop by heaping teaspoonfuls onto cookie sheets that have been coated with nonstick vegetable cooking spray.  Bake for 7 to 10 minutes.  Remove to wire racks to cool.  Frost the flat side of each cookie, one half with vanilla frosting and the other with the chocolate.