Preheat the oven to 350°F (175°C) and line a 9×9-inch baking pan with parchment paper.
In a food processor, combine the flour, sugar, and salt. Pulse to mix.
Gradually add in the cold butter pieces, one at a time, pulsing between each addition. Continue pulsing until the dough forms a crumbly texture.
Add the vanilla extract and pulse to combine. Press the dough evenly into the prepared pan.
Bake for 15-17 minutes, until the shortbread is just starting to brown on top. Leave the oven on.
While the shortbread is baking, prepare the pecan pie topping. In a medium saucepan, combine the pecans, whipping cream, butter, brown sugar, corn syrup, vanilla extract, and maple syrup. Heat over medium heat until the mixture begins to bubble.
Once the shortbread is done, carefully pour the hot pecan mixture over the warm shortbread, spreading it evenly.
Return the pan to the oven and bake for another 15 minutes.
Remove from the oven and let the bars cool for 20 minutes at room temperature. Then, transfer the pan to the fridge and chill for 1 hour.
Once completely cooled, lift the bars out using the parchment paper. Remove the parchment, and slice into bars using a sharp knife heated under hot water for easier cutting.
Store in an airtight container in the fridge, or freeze for up to 4 months (see notes for freezing tips).