These were a hit after Christmas dinner. I frosted half the pan and opted for an unfrosted piece for myself. It was incredibly rich and delicious! Really, I don't think frosting is necessary at all. I used Tollhouse mini chocolate chip cookie dough and only used 36 of the 40 pieces. It covered most of the brownie. Since I only have a dark, nonstick 9x9 pan, I reduced the oven temp a little to 315. I baked for 25 minutes, placed cookie dough and remaining brownie batter, and then I had to cook it for an additional 40 minutes to get a toothpick to come out clean an inch away from the side of the pan.