Preheat your oven to 350°F (175°C). Line a 9×13 inch baking pan with parchment paper and lightly grease it.

In a saucepan over medium heat, melt the unsalted butter until it turns golden brown and emits a nutty aroma, about 5-7 minutes. Let it cool for a few minutes.

In a large mixing bowl, combine the cooled brown butter, granulated sugar, and brown sugar. Mix until smooth and creamy.

Whisk in the eggs one at a time until fully incorporated, followed by the vanilla extract.

In another bowl, whisk together the flour, baking powder, baking soda, salt, and ground cinnamon. Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Pour the cookie batter into the prepared baking pan and spread it out evenly with a spatula.

Bake in the preheated oven for about 20-25 minutes, or until a toothpick inserted in the center comes out clean.

Once baked, remove from the oven and let it cool in the pan for about 10 minutes before lifting it out to cool completely on a wire rack. Cut into bars and serve with a sprinkle of additional cinnamon sugar on top!