In a stand mixer fitted with the paddle attachment, cream butter, powdered sugar, vanilla, and salt until smooth. Gradually add flour and mix on low until combined. Add Andes baking chips and continue mixing on low until fully combined.
On wax paper or parchment paper, form into a 12- to 14-inch log and freeze at least 30 minutes or until firm.
When ready to bake, preheat oven to 350°F. Cut the shortbread dough into ¼ -inch slices and bake for 13 to 15 minutes on parchment lined baking sheets.
Notes
If you want to make these even more festive, dip cookies halfway into melted chocolate and sprinkle with crushed candy canes.
Dough logs can be frozen for up to one month. Wrap well and label. Allow the logs to warm up at room temperature for a half hour before slicing and baking as directed.