Brush bottom and sides of crust with egg yolk. Place on baking sheet. Bake at 350°F for 5 minutes. In small mixing bowl beat eggs and salt with electric mixer on high speed about 5 minutes or until thick and lemon colored. Add brown sugar and vanilla, mixing until combined.
Add chocolate, mix well. Stir in cookies. 3. Spread chocolate mixture in crust. Bake on baking sheet at 350°F for 35 minutes. (Center will be soft.) Cool at least 1 hour on wire rack. Serve with whipped topping.