Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper or a silicone baking mat.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Beat in the egg and vanilla extract until well incorporated.
In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, mixing until a soft dough forms.
Fold in the finely chopped pecans, ensuring they are evenly distributed throughout the dough.
Using a cookie scoop or a teaspoon, drop spoonfuls of dough onto the prepared baking sheet, leaving some space between each cookie as they will spread during baking.
Flatten each cookie slightly with the back of a spoon to achieve a thin and delicate shape.
Bake the cookies for approximately 10 minutes or until the edges turn golden brown.
Remove the baking sheet from the oven and let the cookies cool on it for a few minutes before transferring them to a wire cooling rack to cool completely.