Preheat the oven to 350°F (175°C) and line a 9×9-inch baking pan with parchment paper.
Beat the softened butter, sugar, vanilla, and salt until smooth and creamy.
Gradually mix in the flour until a soft dough forms.
Press the dough evenly into the bottom of the prepared pan.
Bake the crust for 15–18 minutes, until lightly golden around the edges.
Meanwhile, whisk together brown sugar, maple syrup, corn syrup, melted butter, eggs, vanilla, cinnamon, and salt.
Stir the pecans into the filling mixture.
Pour the pecan filling evenly over the warm crust.
Return the pan to the oven and bake for 25–30 minutes, until the filling is set around the edges and slightly soft in the center.
Remove from the oven and allow the bars to cool completely in the pan.
Refrigerate for 1–2 hours for easier slicing.
Lift the bars from the pan using the parchment paper and cut into squares.