In a large bowl, cream together softened butter and granulated sugar until light and fluffy. Beat in egg yolk and vanilla extract. In a separate bowl, whisk together flour and salt. Gradually add dry ingredients to wet, mixing until a soft dough forms. Do not overmix.

Shape dough into a disc, wrap, and refrigerate for at least 30 minutes.

Preheat oven to 350°F (175°C). Lightly grease a mini muffin tin or use mini paper liners.

Take small portions of chilled dough (about 1 tablespoon each) and press them evenly into the bottom and up the sides of each mini muffin cup, forming a small well.

In a medium bowl, combine chopped pecans, melted butter, packed light brown sugar, corn syrup (or maple syrup), egg, vanilla extract, and a pinch of salt. Whisk until well incorporated.

Spoon the pecan pie filling into each prepared cookie cup, filling them about two-thirds full. Do not overfill.

Bake for 18-22 minutes, or until cookie edges are lightly golden brown and the pecan filling is set and bubbly.

Remove from oven and let cool in the tin for 5-10 minutes before transferring to a wire rack to cool completely.