Since I didn't want to dirty my pan, I first lined it with parchment paper. Then dump the mixture into the pan and press with the back of a spoon so that the layer is even. At this point I decided that more chocolate was necessary so I pressed a few chocolate chips into the top of the pan (I have an addiction).
Return to the oven (which is now at 300 F) for 15-30 minutes. It will smell fantastic. For crispier bars leave it in the oven for longer. I wanted mine to be crispier, so I let them bake for 27 minutes.