Preheat oven to 350℉/175℃. Line the bottom of a 9x13 baking sheet with parchment paper.
Use enough parchment paper so extra runs out the sides of the pan. That will help you take them out easier once they're done.
Mix flour, sugar, salt, butter, and vanilla extract in a medium bowl until thoroughly combined.
Pat the dough over the entire bottom of the lined baking pan. Make sure it's evenly distributed; a spatula helps.
In a large bowl, whisk together eggs, brown sugar, flour, salt, vanilla extract, and corn syrup until combined. Then fold in the chopped pecans.
Pour the pecan mixture over the crust.
Bake for 10 minutes, then add the decorative pecan halves if desired. Put it back in the oven and bake again for 30-35 minutes or until the filling is set and a knife inserted 1-inch from the edge comes out clean.
Remove from the oven and let it cool completely—an hour or more—before slicing and serving.
Serve as is or top with ice cream and drizzled with caramel sauce for an indulgent treat.