Cream together butter and sugar until light and smooth.
Mix in vanilla extract, then fold in flour and salt until a soft dough forms.
Roll dough into balls and press an indentation in the center of each cookie.
Chill for 30 minutes while preparing the filling.
In a small saucepan, heat brown sugar, syrup, cream, and butter until slightly thickened.
Remove from heat, stir in vanilla, salt, and toasted pecans, and let cool briefly.
Spoon filling into each cookie indentation.
Bake at 350°F (175°C) for 10–12 minutes until edges are golden.
Cool on a wire rack before serving.