Preheat the oven to 375 degrees F. Spray 14 muffin cups with flour-added baking spray or line with paper liners.Peel the apple, remove the core and chop into very fine bits. I recommend using a mini food processor. You should end up with about 2 1/3 cups.In a small bowl, thoroughly mix together the flour, salt, baking powder, ¾ teaspoon of cinnamon and nutmeg.In a mixing bowl, lightly beat the egg with a fork, then stir in ½ cup of sugar, oil and vanilla.
Add the chopped apple and stir well.
Add the flour mixture and milk alternately, stirring just until blended.Divide the batter among the 14 muffin cups – it should come almost to the top.
Mix together the reserved 1 tablespoon of sugar and ½ teaspoon of cinnamon.
Sprinkle over the top.
Bake the muffins on the center rack for about 25 minutes.
Let cool in the muffin pan. As the cool, loosen gently with edge of a knife, but do not remove. When the muffins are cool, remove from cups.