Preheat oven to 350 degrees. Grease a 9 x 5-inch loaf pan. In a large bowl, mix applesauce, brown sugar, vegetable oil, eggs, and milk.
In a separate bowl (or the same bowl, if you want to be lazy like me), mix all-purpose flour, whole wheat flour, baking soda, baking powder, salt, cinnamon, nutmeg, and allspice. Stir with wet ingredients until just combined.
Using a cheese grater, grate peeled apple directly into bowl, then stir briefly to incorporate. Pour batter into prepared loaf pan and bake 60-65 minutes.