Preheat the oven to 350°F (175°C) and prepare a baking pan.

In a mixing bowl, combine softened butter and brown sugar until creamy.

Add eggs, one at a time, mixing well after each addition, then stir in vanilla extract.

In a separate bowl, whisk together flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Fold in the butterscotch chips until evenly distributed throughout the batter.

Pour the batter into the prepared pan, spreading it out evenly.

Bake in the preheated oven for 25-30 minutes, or until a toothpick comes out clean.

Once baked, remove from the oven and let cool in the pan for at least 15 minutes before transferring to a wire rack.

Cut into squares and enjoy your homemade butterscotch bars.