Preheat the oven to 350 degrees. Line a 9x13 inch baking dish with foil and spray with non-stick spray, set aside.
Place the butter in a large skillet and add the butter. Melt over medium heat, stirring occasionally until the butter begins to foam and deepen in color. Once you see brown bits appear on the bottom of the skillet, remove the pan from the heat and allow the butter to cool for 5 minutes.
Meanwhile, in a large bowl whisk together the flour, baking powder, cinnamon, and salt.
Pour the brown butter into a separate bowl and whisk in the eggs, sugar, and vanilla extract until well combined.
Pour the butter mixture into the flour mixture and stir with a spatula just until combined, then fold in the chocolate chips.
Pour into prepared pan and bake for 20-25 minutes until the top is turning golden brown and the bars are set in the center.
Allow the bars to cool completely before removing from the pan. Store in an airtight container for up to 4 days.
NOTE ON CHOCOLATE: I added a mix of white and semi-sweet chocolate chips. You can leave any chocolate chips out all together if you want. Or, you can use dark chocolate, milk chocolate, cinnamon, or butterscotch!