Step 1: Preheat your oven to 350°F (175°C). Line a 9×9 inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.
Step 2: In a medium bowl, combine the flour, granulated sugar, and salt. Use a pastry cutter or your fingers to work in the cold, cubed butter until the mixture resembles coarse crumbs.
Step 3: Press the crust mixture firmly and evenly into the bottom of the prepared pan. Bake for 15-18 minutes, or until the edges are just beginning to turn a light golden brown.
Step 4: While the crust is baking, prepare the filling. In a large bowl, whisk together the eggs, maple syrup, brown sugar, melted butter, and vanilla extract until smooth.
Step 5: Stir in the chopped pecans until they are thoroughly coated in the maple mixture.
Step 6: Pour the pecan filling over the warm pre-baked crust, spreading it out evenly to the edges.
Step 7: Return the pan to the oven and bake for an additional 25-30 minutes, or until the filling is set around the edges but still has a slight jiggle in the center.
Step 8: Remove from the oven and allow the bars to cool completely in the pan on a wire rack. For the best results, refrigerate for at least 2 hours before using the parchment overhang to lift the bars out and slicing them into 16 squares.