In a large bowl, stir together the oats, flours, salt, baking powder, baking soda, cinnamon and nutmeg.
Cream together the butter and brown sugar until well combined. Add the eggs and vanilla and cream until light and fluffy.
Stir in the shredded apple.
Add the dry ingredients and mix until just combined. Stir in the raisins.
Chill the dough for one hour.
Preheat the oven to 350°F. Line a baking sheet with parchment paper or a silicone baking mat.
Drop the dough by spoonfuls (about 2 tablespoons for each cookie) onto the prepared baking sheet. With damp hands, flatten the cookies slightly. Sprinkle the tops of the cookies with cinnamon sugar, if using.
Bake for 9-10 minutes until lightly browned and set.
Allow to cool for 10 minutes on the cookie sheet before removing them to a wire rack to cool completely.