Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
In a large bowl, cream together the softened butter and granulated sugar until light and fluffy, about 3-4 minutes.
Beat in the egg and vanilla extract until fully combined.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined.
Fold in the toasted, chopped pecans until evenly distributed.
Scoop tablespoon-sized portions of dough and roll into balls. Place on prepared baking sheets, spacing about 2 inches apart.
Bake for 9-11 minutes, or until the edges are lightly golden.
Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Notes
Store in an airtight container at room temperature for up to one week. For best flavor, toast the pecans in a dry skillet over medium heat for 5-7 minutes until fragrant.