Preheat oven to 350°F and line a 9x9 baking pan with parchment paper.

Melt the butter in a saucepan.

Stir in the brown sugar, eggs, and vanilla extract until well combined.

In a large bowl, combine flour, baking powder, and salt.

Mix the wet ingredients into the dry ingredients until smooth.

Pour the batter into the prepared pan and sprinkle with chopped pecans.

Bake for 30 to 35 minutes or until a toothpick comes out clean.

Allow to cool before cutting into squares.