Prepare cookies according to package directions.

While cookies are baking add powdered sugar and butter into the bowl of a mixer and mix until combined.

Slowly add in vanilla and evaporated milk and continue to mix until desired consistency is reached.

Add cinnamon and stir to combine.

Scoop frosting into a piping bag.

Let cookies cool on cooling rack for 5 minutes before adding frosting.

Top bottom of cookie (the flat side) with frosting and place the flat side of a second cookie on top of frosting.