If desired, toast chopped pecans in a dry skillet over medium heat for 4–6 minutes until fragrant, then let cool.

In a large mixing bowl, cream together butter, granulated sugar, and brown sugar until pale yellow and fluffy, about 5–7 minutes.

Beat in the egg until blended, about 1 minute, then add vanilla extract and mix just to combine.

Gently fold in the toasted pecans.

Add flour and salt, mixing on low until the dough just comes together. Do not overmix.

Shape the dough into a log about 2 inches in diameter, wrap in wax paper, and refrigerate for at least 4 hours or overnight.

Preheat the oven to 350°F (177°C).

Remove the dough from the refrigerator, unwrap, and slice into ½-inch rounds.

Place them on an ungreased cookie sheet about 1 inch apart.

Bake for 12–15 minutes until cookies are golden at the edges but still pale on top.

Let the cookies rest on the sheet for a few minutes, then transfer to a wire rack to cool completely.