Step 1: Prepare the Shortbread Crust : Preheat oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper, leaving overhang on the sides for easy removal. In a large bowl, beat softened butter and sugar together until light and creamy. Add flour and salt, mixing until a crumbly dough forms. Press the dough evenly into the prepared pan. Bake for 15–18 minutes, or until the edges are lightly golden. Remove from the oven and set aside to cool slightly.

Step 2: Make the Pecan Filling : In a medium saucepan, combine brown sugar, corn syrup, and butter. Bring to a gentle boil over medium heat, stirring frequently, until the butter is melted and the mixture is smooth (about 3–4 minutes). Remove from heat and stir in heavy cream, vanilla, salt, and chopped pecans. Mix well to coat the pecans evenly.

Step 3: Bake the Bars : Pour the pecan filling over the pre-baked crust, spreading evenly. Return to the oven and bake for 20–25 minutes, or until the filling is bubbling and set. Remove from the oven and let the bars cool completely in the pan (about 2 hours). Once cool, lift out using the parchment overhang and cut into 16 bars.

Step 4: Make the Caramel Drizzle (Optional) : In a small saucepan, combine sugar and water. Heat over medium heat until the sugar dissolves. Increase heat and cook without stirring until the mixture turns deep amber. Remove from heat carefully and whisk in butter and heavy cream (it will bubble vigorously). Add a pinch of salt and stir until smooth. Cool slightly, then drizzle over the cut bars. (You can also microwave store-bought caramel sauce for 10–15 seconds to make it drizzle-ready.)