Preheat oven to moderate 350 degrees. Simmer dates in water in a medium-size saucepan for 10 minutes. Puree mixture in electric blender. Pat 3/4 of the cookie dough evenly in a greased 9x9x2-inch baking pan. Spread date puree over dough. Combine remaining dough and the nuts in a small bowl until crumbly. Sprinkle over date mixture. Pat down gently. Bake in preheated 350 degree oven for 30 minutes. Cool on wire rack. Sprinkle with sifted confectioner's sugar. Cut into bars. Makes 15 bar cookies.