Preheat oven to 350F degrees. Line cookie sheets with parchment paper.
In a medium bowl, stir together dry ingredients (flour, cornstarch, baking soda, salt, nutmeg and cinnamon.) Set aside.
In a bowl (or a stand mixer), cream the sofened butter until smooth.
Add in both sugars and mix until fully incorporated.
Next, add eggs in one at a time, and continue stirring until batter is thoroughly mixed.
If you are using a stand mixer, you'll probably have to take a minute to scrape down the sides to make sure all your batter is mixed properly.
Begin adding in the dry ingredients slowly. Mix well after each addition.
Next, stir in (by hand) the diced apples. Batter will be very thick so this will take a couple of minutes.
In a separate small bowl, combine the cinnamon and sugar mixture.
Scoop out a generous tablespoonful of cookie batter. Drop it into the cinnamon sugar mixture and roll it around.
Put it on the lined cookie sheet and gently press it down to flatten it slightly.
Bake each sheet for 8 minutes. Then turn the baking sheet around and bake for another 8 minutes.
Do not bake more than one sheet at a time or cookies may bake unevenly.
Video
Notes
Don’t pack the flour when measuring. Just dip the measuring cup into the flour, shake off excess then use the flat side of a butter knife to scoop off the excess off the top. This will ensure that you don’t measure out too much flour which will make cookies dry and dense.
Don't over bake these or you'll end up with crispy cookies (unless you like crispy cookies).