Whole Wheat Apple-Cinnamon Muffins

I've tried lots of recipes for healthy low-fat, low-cal foods and they mostly had one thing in common; they taste like cardboard. So I was inspired to come up with a healthy recipe that actually tasted good. These apple-cinnamon muffins are a great accompaniment for a fall dinner, especially served with a hearty beef stew.

Ingredients:
1 egg
1 cup fat free milk
1/4 cup unsweetened applesauce
1 cup all-purpose flour
1 cup whole-wheat flour
3 teaspoons baking powder
1 teaspoon salt
1 Granny Smith apple, grated (it's fine to leave the peel on, just be sure to wash the apple well first)
1 teaspoon cinnamon
1/2 cup chopped walnuts (optional)

Heat oven to 400 degrees. Spray muffin cups with nonstick cooking spray. Beat egg, milk, and applesauce together. Add in remaining ingredients, stir just until moist. Divide batter between muffin cups and bake 20-25 minutes.