Preheat your oven to 350°F (175°C) and grease a 9x9-inch baking dish.
In a bowl, mix the softened butter with brown sugar until creamy.
Add the flour and mix until a dough forms.
Press the dough evenly into the bottom of the prepared baking dish.
Bake the crust for 10-12 minutes, until lightly golden.
In a separate bowl, whisk together the eggs, granulated sugar, corn syrup, vanilla extract, and salt.
Stir in the chopped pecans until evenly combined.
Pour the pecan mixture over the baked crust.
Top with whole pecans, pressing them gently into the mixture.
Bake for an additional 20-25 minutes, until the filling is set.