1.Preheat oven to 375 degrees.
2.Place prunes and water in a food processor or blender and puree.
3.Combine flour, oats, brown sugar, baking powder, salt, if using, and cinnamon in a bowl.
4.In a separate bowl, beat together the prune puree, milk, maple syrup, egg whites, and apples.
5.Stir the wet ingredients into the dry ingredients until the dry ingredients are just moistened.
6.Transfer batter to nonstick or paper-lined muffin cups, or to muffin cups lightly sprayed with vegetable cooking spray.
Bake for 30 minutes or until muffin tops are lightly browned and a wooden tooth-pick inserted into the middle of a muffin comes out clean.
Note: You can substitute 1/3 cup commercially prepared pureed prune