Preheat oven to 350°F (175°C). Line a baking sheet with parchment paper.

Cream softened butter and sugar until light and fluffy. Add egg yolk and vanilla, mixing until combined. Gradually add flour and salt, mixing just until dough holds together.

Scoop and roll dough into tablespoon-sized balls. Place on baking sheet, spacing 2 inches apart. Create an indentation in each ball with your thumb or a spoon.

In a small bowl, combine chopped pecans, brown sugar, corn syrup, melted butter, vanilla, and a pinch of salt. Stir until well combined.

Spoon pecan filling into each indentation, filling to the top.

Bake for 12-15 minutes until edges are golden. Let cookies cool on the baking sheet for a few minutes before transferring to a wire rack.