In a large bowl, whisk the flour, baking soda, baking powder, salt, spices and cider drink mix together. Stir in the oats; set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream the butter until smooth. Add both sugars and beat until pale and fluffy. Add the applesauce, egg yolk, and vanilla, and beat until smooth. Dump in the flour mixture, mixing until just combined. Wrap dough in plastic wrap and chill in the refrigerator for at least 2 hours.
Preheat the oven to 350ºF and line a baking sheet with parchment paper. Using greased hands, roll dough into 1-inch balls, about 2 Tablespoons of dough per cookie. Place dough balls onto prepared baking sheet, leaving 2 inches of space between each one.
Bake for 8-10 minutes, or until lightly browned around the edges. Allow to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Make the Frosting:
In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and cream cheese together on high, until smooth and creamy. Add the caramel and mix until combined.
With mixer on low, slowly add the powdered sugar, a half cup at a time. Once all of the sugar has been added, whip frosting on high for about 30 seconds until light and fluffy.
To Assemble:
Spoon the filling into a piping bag fitted with a large round tip (or gallon zip-loc bag with the tip cut off), and pipe the filling onto the bottom side of a cookie. Gently press another cookie on top, forming a sandwich. Repeat with the remaining cookies and frosting.
Serve immediately, or store leftovers in an airtight container in the refrigerator for up to 5 days.
Notes
*I used Alpine Original Spiced Apple Cider Instant Drink Mix.