Prep Oven and Line Pan: Preheat your oven to 350°F (175°C). Line a 9x13-inch metal or ceramic baking pan with parchment paper, leaving an overhang on the sides for easy lifting later. Lightly grease the parchment with butter or nonstick baking spray.

Make the Shortbread Crust: In a food processor or large bowl, combine all-purpose flour, powdered sugar, cold cubed butter, vanilla extract, and salt. Pulse or cut together with a pastry blender until the mixture forms coarse, sandy crumbs that hold together when pressed. Press the dough firmly and evenly into the bottom of the prepared pan.

Par-Bake the Crust: Bake the shortbread crust at 350°F (175°C) for 18 to 20 minutes until the edges are lightly golden and set. Remove from oven and let sit while you prepare the filling.

Whisk the Pecan Caramel Filling: In a medium bowl, whisk together melted butter, dark brown sugar, pure maple syrup, heavy cream, room-temperature eggs, vanilla extract, ground cinnamon, and sea salt until completely smooth, glossy, and emulsified. Stir in the chopped pecans until evenly coated.

Pour and Bake: Pour the pecan caramel mixture evenly over the warm par-baked shortbread crust, spreading the pecans into a single uniform layer. Bake at 350°F (175°C) for 22 to 25 minutes until the caramel is bubbling vigorously across the entire surface and the center is just set.

Sprinkle Salt & Cool Completely: Remove from the oven and immediately sprinkle flaky Maldon sea salt all over the bubbling top. Let the bars cool completely in the pan on a wire rack for at least 2 hours (or chill for 1 hour in the refrigerator) so the caramel sets firmly for neat slicing.

Slice and Serve: Use the parchment paper overhang to lift the whole block onto a cutting board. Using a sharp chef knife, slice into 16 even squares (wiping the blade clean between cuts for bakery-sharp edges). Serve at room temperature!