To make the dough add flour, chocolate, sugar, and salt in a large bowl. Using a pastry blender cut in cold butter until the mixture resembles coarse crumbs. Press dough into a greased 15 by 10 by one-inch. baking pan. Bake for 20 minutes.
Filling
Meanwhile, melt butter in a medium saucepan over medium heat and whisk in the sugar until smooth and dissolved for three to five minutes. Remove from heat and whisk in corn syrup, rum, vanilla, zest, and salt. Lightly beat eggs in a large bowl, then slowly whisk in the corn syrup mixture. Fold in pecan until evenly distributed.
Bake and Serve
Spread pecan mixture evenly over warm crust then place back in the oven for 30 minutes until filling sets.
Remove from oven and allow to cool on a wire rack.