Preheat the oven to 350° F. Line a 9×13 inch baking dish with parchment paper.Add the butter to a medium pot set over medium heat. Allow the butter to brown, until it smells toasted, about 2-3 minutes. Stir often. Remove the pot from the heat and stir in the pumpkin butter and brown sugar. Let cool 5 minutes. Whisk in the eggs and vanilla. Add the flour, baking powder, cinnamon, and salt, mixing until just combined. Stir in the chocolate chips. Spread the dough out into the prepared dish.Evenly sprinkle the cinnamon sugar over the dough (if desired), then add a handful more of chocolate chips. Bake for 25-30 minutes, just until set in the center. Let cool. Cut into bars…snack and enjoy!