In a large bowl, cream together the shortening and sugar until smooth. Beat in the eggs one at a time then stir in the vanilla.
Combine the flour, cocoa, baking powder and salt; stir into the creamed mixture. Stir in walnuts if desired. Cover dough and chill for at least one hour.
Preheat oven to 350 degrees F (175 degrees C).
Roll the dough into walnut sized balls.
Roll the balls in confectioners' sugar.
Place the cookies 2 inches apart onto the cookie sheet.
Bake for 10 to 12 minutes in the preheated oven. Allow cookies to cool on baking sheet for 5 minutes before removing to a wire rack to cool completely.
