Preheat the oven to 350°F. Lightly grease a 9" square pan., In a medium-sized mixing bowl combine the flours, baking soda, salt, xanthan gum, cinnamon, and nutmeg. Set aside., In a separate bowl, stir together the brown sugar and oil, then beat in the eggs until well blended., Stir the dry ingredients into the wet ingredients, and mix until evenly moistened., Stir in the apples, dried cranberries, and walnuts until well incorporated. Pour the batter into the prepared pan., Bake the cake for 45 to 55 minutes, or until it's golden brown and a toothpick inserted into the middle comes out clean., Remove the cake from the oven, and allow it to cool in the pan for 10 minutes before turning it out onto a rack., Serve the cake warm, or cool completely and frost with cream cheese frosting, if desired., Store any leftover cake in an airtight container at room temperature for several days, or freeze for longer storage.