In the bowl of a stand mixer fitted with the paddle attachment, add the cream cheese, sweetened condensed milk, butter, brown sugar, and salt.
Beat on high speed for 2-3 minutes, until smooth and creamy.
Add the confectioners sugar, one cup at a time, beating for 1 minute in between additions.
Add the mini chocolate chips and beat until just combined.
Transfer the filling to a large piping bag and set aside.
On a large baking sheet, lay out one layer of chocolate wafer cookies, in the middle of each chocolate wafer cookie, pipe ~1 ½ Tablespoons of filling.
Place another chocolate wafer cookie on top and gently press to attach.
Place the tray in the refrigerator for 20 minutes.
After the cookies have been slightly chilled, remove them from the refrigerator. In a small bowl, melt the white chocolate in 30 second intervals until smooth and fully melted.
Transfer the melted chocolate to a small zip top bag and snip off one of the corners.
Drizzle the chocolate overtop of the sandwich cookies.
Return the cookies to the refrigerator and let chill for 2 hours before serving.
Notes
Cookies should be stored in an airtight container and kept in the refrigerator for up to 5 days.
Cookies can also be stored in the freezer for up to 3 months.