Apples, cinnamon, and nutmeg make these muffins taste like fall.
Adjust oven rack to middle position and heat oven to 375 degrees. Spray 12-cup muffin tin, including top, with vegetable oil spray.
In medium bowl, whisk together all-purpose flour, whole-wheat flour, baking soda, and salt.
In large bowl, whisk together sugar, cinnamon, and nutmeg. Transfer 2 tablespoons sugar mixture to small bowl and reserve for sprinkling.
Add applesauce, melted butter, cider, egg, and vanilla to remaining sugar mixture in large bowl and whisk until well combined.
Add flour mixture and use rubber spatula to gently stir until just combined and no dry flour is visible. Do not overmix.
Spray ¼-cup dry measuring cup with vegetable oil spray. Use greased measuring cup to divide batter evenly among muffin cups. Sprinkle reserved sugar mixture evenly over batter in each muffin cup.
Spray measuring cup or measuring spoon needed for portioning in recipe with vegetable oil spray.
Scoop batter with greased measuring cup or spoon and scrape off any extra batter that is dripping from the bottom or overflowing on top. This ensures that all muffins will be equal in size and that there will be enough batter to fill all muffin tin cups.
Pour batter into muffin tin cup, using a rubber spatula to scrape batter from measuring cup or spoon if needed.
Place muffin tin in oven. Bake until muffins are deep golden brown and toothpick inserted in center of 1 muffin comes out clean, 20 to 25 minutes.