Preheat oven to 300 degrees F (150 degrees C). Grease and flour a 10 inch tube pan.
In a large bowl, combine dates, walnuts, sugar, baking powder and flour. Stir in egg yolks. In a large glass or metal mixing bowl, beat egg whites until stiff peaks form. Fold the whites into the fruit/nut mixture until no streaks remain. Spoon into prepared pan.
Bake in the preheated oven for 90 minutes. Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.