01 - Preheat oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper, allowing an overhang for easy removal.
02 - In a medium saucepan over medium heat, melt the butter and cook, stirring frequently, until it turns golden brown and gives off a nutty aroma, about 5 to 7 minutes. Immediately transfer to a large mixing bowl to cool slightly.
03 - Add brown sugar to the cooled brown butter and mix until well combined.
04 - Beat in eggs one at a time, followed by the vanilla extract, mixing until smooth.
05 - Whisk together flour, baking powder, and salt in a separate bowl. Gradually stir into the wet mixture until just combined.
06 - Gently fold chopped pecans into the batter, ensuring even distribution.
07 - Spread batter evenly in prepared pan. Bake for 25 to 30 minutes, or until edges are set and center is golden but still soft. Cool completely in pan before lifting out and cutting into bars.