Arrange crust (if it's the kind you unroll) into a deep dish pie pan.
In a large saucepan, whisk together brown sugar, corn syrup, molasses, butter, and salt.
Bring to a simmer over medium heat, and cook just until sugar is dissolved, about 3 minutes.
Remove from heat, and add vanilla and dark rum.
Allow mixture to cool to room temperature.
Whisk in the eggs, pecan halves, and chocolate chunks.
Pour into pie crust.
Bake at 350 degrees for about 50 minutes, or until edges are golden brown, and the center is set.
Remove to a wire rack to cool.
Cut and serve, topped with whipped cream.