Scatter pieces of cookie dough over the top of the brownie batter. In my 8×8 square pan, I was able to get about ⅔ of the cookie dough to fit over the brownies and I just saved the rest for regular cookies. Press gently on the dough just until it starts to sink down into the batter a little bit.
Bake for 35-40 minutes (35 for gooey, 40 or more for fully baked), covering with foil if you need to keep the cookies from getting too brown on top. Let stand for 15-20 minutes and cut into pieces for serving.
Beware of taking these out too early because the cookies look brown – usually when I do that, the brownies are still underdone and they sink down in the middle. I found that it was easiest to alternate baking them covered and uncovered. I did the first 20 minutes uncovered, the next 10 minutes covered, and the last 5 minutes uncovered. This allows the brownies to bake without the cookies getting too brown. I’ve also taken foil and just made a cover around the edges so the middle can bake without burning the tops of the edges.