Combine the flour, baking powder and salt in a small bowl and set aside.
Cream together the shortening and sugar until fluffy. Add the vanilla and mix until combined. Add the eggs, one at a time, and combine until well-blended. Add the chocolate and mix.
Add the milk and flour mixture, a little at a time, alternately to the chocolate mixture and mix until just combined. Stir in the walnuts, if using.
Chill the dough overnight.
Pre-heat the oven to 350°F. Form the dough into 1-inch balls and roll the balls in confectioners’ sugar. Bake on greased cookie sheet for 14-16 minutes.