In a large bowl, combine the butter, brown sugar, eggs and vanilla until creamy.
To a separate bowl, add the flour, oats, cinnamon, baking soda and salt and stir to combine.
Gradually add the dry mixture to the wet mixture until just combined.
Line two baking sheets with parchment paper and use an ice cream scoop to drop the cookie dough onto the baking sheets. Press the cookie balls down slightly and allow enough room for the cookies to spread during baking.
Bake the cookies at 350 degrees for 13-15 minutes.
Let the cookies cool, then add a scoop of frosting to the bottom side of one cookie. Top the frosting with another cookie to form the wookiee cookies.
To Prepare the Frosting:
In a large bowl, mix the butter, cream cheese and vanilla together.
Add the powdered sugar 1 cup at a time and mix well.
Chill the frosting in the refrigerator until ready to use.
To Prepare the Chocolate Topping:
Melt the chocolate chips in one bowl and the white chocolate chips in a separate bowl.
Add the melted chocolate and melted white chocolate to two separate piping bags.
Pipe the chocolate into long rectangles on a baking sheet lined with parchment paper. Allow the chocolate to set in the refrigerator for 15-20 minutes.
Add small white dashes to the chocolate rectangles using the white chocolate. Allow the chocolate to set in the refrigerator for another 15-20 minutes before adding to the wookiee cookies.