Preheat oven to 325 degrees.
Cream butter and sugar. Add eggs one at a time and beat until light and fluffy. Add vanilla. Sift 2 cups flour, salt and baking powder together. Add sifted ingredients to creamed mixture and beat. Dredge berries in remaining flour. Gently fold floured berries into the batter. Grease and dust a tube pan with confectioners' sugar or flour; pour batter into it. Bake for 1 hour and 15 minutes, or until it tests done.