Preheat oven to 350 degrees. Cut a piece of parchment paper to fit the bottom of a 9-inch cake pan or 8x8 inch square baking pan. Spray pan liberally (bottom and sides) with vegetable spray. Place the parchment in the bottom of the pan and spray the parchment with vegetable spray. Set aside.
In a 2 cup glass measuring cup add the buttermilk, applesauce, egg, rum and vanilla. Whisk to combine. Set aside.
In a large mixing bowl combine the flour, brown sugar, baking soda, baking powder, cinnamon, cloves, nutmeg, allspice and salt. Whisk until well combined then stir in the liquid ingredients, shredded apple, walnuts and raisins. Stir several times to assure that dry ingredients are blended into the wet and that the solids are evenly distributed throughout the batter.
Pour the batter into the pan and bake for 40-45 minutes or until a cake tester comes out clean.
Cool on a wire rack to room temperature and dust with powdered sugar if desired.