Beat butter and 3/4 cup of the sugar together at medium speed, until light and fluffy. Stir in 1 cup of the black walnuts and mix well. Combine dry ingredients and stir in to form dough. Roll 1/2 inch thick. Mix remaining sugar and black walnuts, sprinkle on top of dough. Roll to 1/4 inch thick. Cut into desired shape. Place on ungreased cookie sheet. Bake at 375° for 8 to 10 minutes or until beginning to brown.