1. Grease a 9 inch pie pan. 2. Add melted butter to chocolate cookie crumbs and mix until combined. 3. Press mixture evenly onto the bottom and sides of plate. 4. To make the filling, melt butter in a large saucepan. 5. Add brown sugar and heavy cream and whisk over medium heat until sugar is dissolved. 6. Remove from heat and allow to cool for about 10-15 mins. 7. Pour caramel layer into pie crust. Place in refrigerator for 2 hours. 8. Place semi sweet chocolate chips into a bowl. 9. Microwave heavy cream until it begins to bubble, then pour over chocolate. 10. Whisk chocolate until smooth. 11. Fold in walnuts into the chocolate mixture. 12. Pour over the caramel layer and refrigerate until set. 13. Top with whipped cream.