Preheat oven to 300°F (148°C).

In a medium sized mixing bowl, beat butter with a hand mixer until creamy.

Next, gradually add the sugar, beating well between each addition until light and fluffy.

Next, add the egg yolk and mix to combine.

Next, add the flour and beat on low and keep mixing until well combined and the dough forms.

Next, add the vanilla and mix to combine.

Shape dough into 1 ½ inch balls and place on a parchment lined baking sheet. Gentry press a pecan half in the center of each cookie.

Bake 16-18 minutes or until lightly browned.

Allow the cookies to cool slightly then transfer to wire cooling racks and cool completely.