Heat oven to 325 degrees. Position rack in bottom third of the oven. Butter and flour a 9X3 inch tube pan, or spray with nonstick cooking spray.
In large bowl, whisk together the flour, salt, and soda. In the bowl of an electric mixer, cream the butter and sugars at medium high speed until light and fluffy, about 3 minutes. Beat in the eggs, one at a time, mixing well after each addition. Add the flour mixture alternately with the buttermilk. Mix in the extracts and zests, and fold in the prunes.
Bake for one hour, until the cake pulls away from the pan, and a toothpick inserted into the cake comes out clean.
To Make Brandy Soaked Prunes.
Empty a 16 ounce container of prunes into a clean, sealable glass jar and pour brandy over the top until it covers them by about an inch. Allow prunes to macerate at least one day before making cake. Kept in a cool, dark place, the prunes will keep for months.