In a mixing bowl, combine flour and sugar. Cut in shortening until mixture resembles coarse crumbs; set aside 1 cup for topping. To the remaining crumb mixture, add eggs, buttermilk, baking powder and baking soda; beat until smooth. Fold in dates and walnuts.
Transfer to a greased 13-in. x 9-in. x 2-in. baking pan; sprinkle with reserved crumb mixture. Bake at 350 degrees F for 25-30 minutes or until a toothpick inserted near the center comes out clean. Cool on a wire rack.