Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the butter, brown sugar, and sugar. Cream until light and fluffy, about 3-4 minutes.
Add the lightly beaten egg and vanilla. Beat until well combined.
Gradually mix in the all-purpose flour until just incorporated.
Gently fold in the chopped pecans with a spatula.
Drop rounded balls of dough onto a baking sheet lined with parchment paper, leaving about 2 inches between each cookie. Bake for 10-12 minutes.
Let the cookies cool on the baking sheet for about 5 minutes before transferring them to a cooling rack. Dust with powdered sugar before serving.
