Combine dates, granulated sugar and water in a medium saucepan; bring to boiling. Reduce heat and simmer, stir over medium-low heat for 3 minutes or until water is absorbed and mixture is thick, stirring constantly to prevent scorching. Stir in vanilla and ground nuts. Cool.
Beat shortening, granulated sugar, and brown sugar in a very large mixing bowl. Add eggs and vanilla; beat well. Stir together 2 cups of flour, the baking soda, cinnamon, cream of tartar, and salt in a medium bowl. Add to sugar mixture; beat well. Beat or stir in the remaining flour to make a firm dough. Divide dough into two portions; wrap and chill until easy to handle.
Roll half of the dough on a lightly floured surface into a 13x9 inch rectangle and 1/4 inch thick. Spread with half of the filling. Roll up jelly-roll style, starting from one long edge. Cover the roll with plastic wrap and refrigerate for 2-24 hours. Repeat with remaining dough and filling.
Slice and roll into 1/4 inch thick slices. Place about 2 inches apart on a lightly greased cookie sheet. Bake in a 350 degree Fahrenheit oven about 8 minutes or till lightly browned. Cool on wire rack. Store in tightly covered container.