Easy Applesauce Muffins

In a medium bowl, sift together both flours, baking soda, salt, ½ teaspoon cinnamon, and nutmeg. Whisk to combine.  In a large bowl, whisk together melted butter, light brown sugar, ½ cup granulated sugar, vanilla, applesauce, and the egg. Add the dry ingredients to the wet ingredients in two additions, stirring until just combined.  In a small bowl, combine remaining 3 tablespoons granulated sugar and remaining ½ teaspoon cinnamon. Coat cups of muffin tins with nonstick cooking spray, and sprinkle 2/3 of the sugar in the bottom and around the sides of each cup, saving ⅓ to sprinkle on top of the muffins.  Divide muffin batter evenly between the cups (about ¼ cup per muffin), and sprinkle tops with remaining cinnamon sugar. Bake, rotating halfway through, until a toothpick inserted in the center of the largest muffin comes out clean, 17 to 20 minutes.