Preheat your oven to 350°F. Grease a 9x9-inch baking dish, then line it with parchment paper that overhangs two sides.
Pulse the graham cracker crumbs and sugar together, then add the melted butter and pulse until it looks like wet sand. Press it firmly and evenly into the bottom of the pan and bake for 10 minutes.
Beat the cream cheese, sugar, eggs, vanilla, and salt together until completely smooth, about 4 to 5 minutes. Spread it over the warm crust and bake for 25 to 30 minutes, until the edges look set and only the very center still has a slight jiggle.
Bring the brown sugar, corn syrup, heavy cream, butter, and salt to a boil in a saucepan over medium heat, stirring constantly. Let it boil for one more minute, then pull it off the heat and stir in the vanilla and chopped pecans.
Let the pecan mixture cool for about 5 minutes, then pour it slowly over the cheesecake layer. Bake for 30 to 40 minutes, until the pecan layer looks deep golden and bubbly at the edges.
Let the bars cool completely at room temperature, then cover and refrigerate for at least 4 hours, or overnight.
Use the parchment overhang to lift the whole slab out of the pan, then slice into 16 squares with a sharp knife.