Preheat oven to 350°F.
Combine corn syrup, sugar and salt in a small saucepan. Bring mixture to a boil over medium heat, stirring until sugar is dissolved. Boil for 2 minutes. Remove from heat.
Add chocolate and butter to syrup mixture, stirring until chocolate is melted and mixture is smooth. Let cool.
Slowly pour chocolate mixture over eggs, stirring constantly. Add vanilla and pecans; mix well. Pour mixture into pie crust.
Bake for about 50 minutes, until center of pie is slightly puffed; cool. If desired, top with whipped cream.