How to Make It
Place chocolate in a small heatproof bowl. Place heavy cream in a microwavable bowl; microwave at high until hot, 30 to 45 seconds. Pour over chocolate; stir until smooth and melted. Spread chocolate mixture in an even layer on bottom of frozen pie shell. Freeze, uncovered, until hard, at least 1 hour or up to overnight.
Preheat oven to 350°F. Whisk together corn syrup, eggs, brown sugar, flour, butter, molasses, vanilla, and salt in a bowl. Sprinkle walnuts over chocolate layer in frozen pie shell; pour corn syrup mixture over walnuts. Bake in preheated oven until edges are set, about 1 hour. Transfer pie to a wire rack to cool completely, about 4 hours.