Stir together flour and baking powder and set aside.
Beat together eggs and sugar in a large bowl until well blended. Stir in butter, extracts, black walnut flavoring and the walnuts. Gradually stir flour mixture into creamed mixture, blending well.
Divide dough on a floured surface into 8 equal portions. Roll each portion into a 14 inch rope.
Place four ropes about 2 inches apart on greased cookie sheet. Bake in a 325 degree F (165 degree C) oven for approximately 20 minutes, until bottoms are pale gold in color.
Let cool about 2 minutes on the baking sheet. Use a serrated knife to cut each rope on a diagonal into slices 1/2 to 3/4 inch thick. Lay slices close together on their sides and bake at 375 degrees F (190 degrees C) until lightly toasted (approximately 15 minutes). Cool completely on the baking sheet. Store airtight.