Preheat your oven to 350°F (175°C).

Grease a 9" x 13" baking dish with non-stick cooking spray.

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

In a large mixing bowl, beat the softened butter and brown sugar until smooth. Add the eggs and vanilla, mixing until well combined.

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

Spread the batter evenly in the prepared baking dish.

In a small bowl, combine the granulated sugar and ground cinnamon. Sprinkle over the batter.

Bake for 25–30 minutes or until lightly golden.

Let cool for at least 15 minutes before cutting into squares.