Rinse and drain sauerkraut; chop coarsely. Bring butter to room temperature. Using a fork, combine flour, cocoa, salt, baking powder, and baking soda in large bowl. Cream butter at medium speed with an electric mixer. Gradually add sugar; add eggs one at a time, then vanilla. Alternately, add flour mixture and water or coffee, beginning and ending with flour. Stir in sauerkraut and pour into two greased and floured 8-inch round or square pans. Bake at 350°F for 25-30 minutes. Fill and frost with a chocolate fudge frosting, or mocha whipped cream.