Preheat the oven to 350ºF. Coat a 9-by-13-inch baking pan with nonstick cooking spray and line with parchment paper, extending the paper over the edges for easier removal.

For the pecan filling, in a large bowl, whisk together the brown sugar, flour, cornstarch, and salt until there are no lumps.

In a separate bowl, whisk together the eggs, corn syrup, melted butter, and vanilla. Add the liquid mixture to the dry mixture and whisk until combined. Let the mixture stand while preparing the crust.

For the crust, in a large bowl, stir together the flour, icing sugar, vanilla, and salt. Add the melted butter and stir until combined. Press the dough onto the bottom of the prepared pan. Poke the crust with a fork 5 or 6 times in different locations to prevent air bubbles. Bake the crust in preheated oven for 20 minutes, until golden.

Stir the pecans into the pecan filling and pour the filling evenly over the crust. Bake at 350ºF for 45 minutes until the filling is just set; the center should be a little wobbly but not runny. Cool completely, refrigerate, and chill at least 2 hours before cutting.