Mixed Berry Slab Pie with Chocolate

"This makes a massive slab pie, easily serving a small army or a few teenagers. At first it may seem intimidating to roll the dough so large then transfer it to the 1/2 sheet pans, but this dough handles quite easily and if you happen to break it, you can always patch with dough scraps. If you have less to feed, then you can always divide the recipe in half and use a 1/4 sheet pan, but there are always neighbors who will take the leftovers so we encourage you to give the full recipe a shot!..."