Preheat the oven to 350 degrees. Grease a 10" baking pan (8" or 9" pans will work as well, simply add a few minutes to the baking time). Stir together the Biscoff, butter, brown sugar and eggs until smooth and creamy. Add the flour, baking powder and salt and stir to combine. Add the chocolate chips and the nuts and stir once more.
Spread the mixture in the prepared baking pan. Bake for 23-25 minutes, until a toothpick inserted comes out mostly clean. Serve warm, topped with your favorite ice cream or let cool and slice into bars. Enjoy!