I fixed this a few weeks ago with my daughter when it was just way to hot to be outside. I used a chocolate chip cookie recipe that was included with my Kitchen Aide Mixer. The recipe was for cookies, but I adapted it for a 8x12 cake pan. I followed the recipe until it came time to dish it all out, then I just simply placed the cookie dough into the pie pan and baked it at the same temperature as the recipe four about 30 minutes when the dough was nice and golden brown. The end result was delicious and I will be repeating this again, but with one slight change. The recipe makes enough dough for 54 cookies, so there is easily enough dough to fill a large bar pan. Which I'm sure would cook much more evenly and be a little closer to a cookie serving size making it much easier for those concerned about their calorie intake.
On a side note, I recently contacted Target about their Market Pantry Chocolate Chips and if they were produced on shared equipment. They stated that they are not produced on shared equipment and in fact safe for those with Peanut Allergies. This is a huge relief for us for two reasons; one being that their safe for our little girl and two, because its incredibly convenient since we don't have to special order them off of the internet.
1 cup brown sugar
1 cup (2 sticks) butter or margarine, softened
1 1/2 teaspoons vanilla
1 teaspoon baking soda
1 teaspoon salt
3 cups all-purpose flour
12 ounces semi-sweet chocolate chips
Place sugars, butter, eggs, and vanilla in mixer bowl. Attach bowl and flat beater to mixer. Turn to Speed 2 and mix about 30 seconds. Stop and scrape bowl. Turn to Speed 4 and beat about 30 seconds. Stop and scrape bowl.
Turn to Stir speed. Gradually add baking soda, salt, and flour to sugar mixture and mix about 2 minutes. Turn to speed 2 and mix about 30 seconds. Stop and scrape bowl. Add chocolate chips. Turn to Stir Speed and mix about 15 seconds.
Drop rounded teaspoonfuls onto greased baking sheets, about 2 inches apart. Bake at 375ºF for 10 to 12 minutes. Remove from baking sheets immediately and cool on wire racks.
For the cookie cake place the cookie dough in a large greased bar pan or a 9x13 pie pan. Bake at 375ºF for 30 minutes or until the cookie dough has turned a golden brown. Remove from the oven and allow pan to cool on a wire rack.