Preheat oven to 350°F. Line a baking sheet with foil and spray with nonstick baking spray.v
In a large bowl, beat the butter and sugar until creamy. Add the apple butter and vanilla and beat again.
In a medium bowl, stir together the salt, flour, cinnamon, and nutmeg. Slowly add to the dry mixture to the wet mixture and stir until dough forms.
Place the dough on the prepared pan. Press the dough out evenly into a 9 X 11 rectangle. Bake for 11-12 minutes.
Remove from oven and use a pizza cutter to cut the warm cookie into 20 even rectangles. Let cool for a few minutes on the pan, then remove them to a wire rack to cool completely.
Whisk together the apple butter, butter, and powdered sugar. Use a spatula to spread the frosting evenly on the tops of the cooled cookies.
Place the melted white chocolate in a plastic bag and cut tip off one end. Drizzle white chocolate over the tops of the frosting. Let sit until the frosting hardens.
Store in a tightly sealed container.