USe 1 tablespoon of the butter to grease an 8-inch tube cake pan. Dust with a tablespoon of the flour. Set aside. Pre-heat oven to 325 degrees.
Beat together the eggs, sugar, vanilla and baking powder. Melt remainder of the butter and add it, mixing well. Gradually stir in the flour, beating with a wooden spoon until well blended. Add, dates, raisins and walnuts and stir again to distribute them evenly through the batter. Pour mixture into the prepared panand bake about 30 minutes, until a knife inserted into the center comes out clean.