Preheat oven to 375˚F. Line muffin pan with paper liners, or lightly spray a muffin pan.
In a medium bowl, combine the flour, baking powder, baking soda, salt, cinnamon and nutmeg.
In a large bowl, cream together the butter, brown and white sugar until light and fluffy. Add the eggs and vanilla and beat well. Slowly add the flour mixture, mixing until fully incorporated. Fold in the apples.
Spoon the batter into the prepared muffin pans. Sprinkle the tops with sanding sugar.
Bake in the preheated oven for around 15 minutes, or until a toothpick inserted comes out clean. Place on wire racks to cool completely.