Preheat the oven to 350ºF (180ºC). If you have a baking steel or stone, put it on the middle rack of the oven. Otherwise invert a rimmed baking sheet, if you have one, on the rack to even out the heat. If you don't have any of those, it's okay to bake the pie without it. Melt the 6 tablespoons of butter in a saucepan over medium heat until it starts to foam. Add the brown sugar, corn syrup (or another liquid sweetener), and maple syrup and stir until smooth. Remove from heat and let cool until tepid, about 5 minutes.
Whisk in the the bourbon (if using), salt, and vanilla. Then whisk in the eggs one by one, until they're completely incorporated. Stir in the chopped pecans.
Scrape the pecan filling into the prepared pie shell, fold the overhang of dough over the pecan filling, and bake on the prepared middle rack of the oven until the center feels almost set in the center. Mine took 30 minutes, although in her book, Cathy says it'll take 55 minutes, so start checking it at the 30 minute mark.
Remove the pecan pie from the oven and let cool completely.
Melt the chocolate in a small, absolutely dry, heatproof bowl set over a pan of barely simmering water, stirring until smooth. Transfer the melted chocolate to a pastry bag fitted with a small plain tip, or into a sturdy zip-top bag. Snip off one of the corners of the plastic bag, or use the pastry bag fitted with a tip, to scribble the chocolate over the pie. Refrigerate the pie until the chocolate has firmed up. (Alternately, you could serve it with soft chocolate on top.)