Preheat oven to 325°F. Leave dates and nuts whole; place in mixing bowl, sift the flour, salt, and baking powder over them. Mix carefully, add sugar and mix again.
Beat yolks until light and thick. Add vanilla and stir into dry ingredients.
Beat egg whites until stiff and fold in until well blended. Bake in a shallow loaf pan lined with buttered paper, for 1 hour.