Whisk flour, salt, cinnamon and nutmeg in a medium bowl and set aside.
In the bowl of a stand mixer (see note), add butter, cream cheese, sugar and vanilla; beat on medium speed with the paddle attachment until pale and fluffy, or about 2 minutes.
With mixer on low speed, add dry ingredients until just combined. Add dried apples and mix only until combined.
On a sheet of parchment paper, shape the dough into a log about 2 inches in diameter. Wrap up in parchment paper and freeze until firm, or at least one hour.
Preheat oven to 350°F. Remove dough from freezer and roll in chopped walnuts. Slice into ¼ inch slices (roll the outside in walnuts again after slicing if necessary) and place on a baking sheet lined with parchment paper.
Bake until golden brown around edges, or about 16 to 18 minutes. Cool for 2 to 3 minutes on baking sheet before transferring cookies to a wire rack to cool completely.
Notes
Yield will vary depending on the diameter of your dough rolls and the thickness of the slices.
If you don't have a stand mixer, a hand mixer will work as well. You may have to stir in the dry ingredients by hand.
Make ahead tip: Cookie dough logs, well-wrapped, can be frozen for up to 3 months. Let thaw slightly before slicing. Bake as directed.