Sift flour, baking powder and salt into a large bowl. Set aside.
Stir brown sugar into softened (not melted) butter in another large bowl until butter disappears.
You can use the back of your spoon to help incorporate the two together.
Add eggs one at a time to butter mixture and stir well after each egg.
Add vanilla, chocolate chips and nuts, mix well.
Add dry flour mixture and stir until well combined.
Coat a 13 X 9 pan with non-stick spray and spread batter evenly into dish.
Bake at 350 F degrees for 30 minutes or until top is golden brown. Make sure you don’t over bake.
Notes
FYI: If the bars aren't done in 30 minutes and the tops feel like they are getting too brown, then place a sheet of aluminum foil on top and bake a little longer. Use a toothpick to check the doneness before removing from the oven. Also make sure you sifted the dry ingredients and used room temp butter, not melted. The batter should be thick.
Recipe by It Bakes Me Happy at http://itbakesmehappy.com/2010/05/congo-bars.html