Step 1: Preheat your oven to 350°F (175°C) and grease a 9×9 inch baking pan or line it with parchment paper for easy removal.
Step 2: In a large bowl or food processor, combine the flour, granulated sugar, salt, and cold cubed butter. Pulse or use a pastry cutter until the mixture resembles coarse meal.
Step 3: Press the crust mixture firmly and evenly into the bottom of the prepared pan. Bake for 15 minutes until the edges are just barely starting to turn golden.
Step 4: While the crust bakes, whisk together the eggs, maple syrup, brown sugar, melted butter, and vanilla extract in a medium bowl until smooth.
Step 5: Stir the chopped pecans into the maple mixture until they are well coated.
Step 6: Pour the pecan filling over the hot, pre-baked crust, spreading it out to the edges.
Step 7: Return the pan to the oven and bake for another 20-25 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 before slicing into 16 squares.