Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large mixing bowl, cream together softened unsalted butter with brown sugar and granulated sugar until light and fluffy, about 2-3 minutes.

Add the large eggs one at a time, mixing well after each addition. Stir in the vanilla extract and scrape down the sides of the bowl.

In a separate bowl, whisk together all-purpose flour, baking soda, and salt. Gradually add this to the wet mixture, stirring gently until just combined.

Fold in the old-fashioned oats and chopped pecans until evenly distributed.

Drop rounded tablespoons of dough onto prepared baking sheets, spaced about 2 inches apart.

Bake in the preheated oven for 10-12 minutes until edges are golden brown and centers are set but still soft.

Cool on baking sheets for about 5 minutes before transferring to wire racks.