Once the dough has doubled, punch it down then turn it out onto a well floured surface. Divide the dough into four equal pieces. (or two or three, depending on the size skillet you're using. You can also freeze half the dough for later use).
Place a cast iron skillet (or several, if you have them) on the stove top and turn the burner to high heat. If it gets too smoky, turn it down a bit, but you want it to be really hot.
Place an oven rack as close to the broiler as possible so that the cast iron pan will still slide underneath. Preheat the broiler to high.
Cover a pizza peel or baking sheet (without rims!!) with a mixture of flour and cornmeal. Place dough ball on top of the flour/cornmeal mixture. Roll out each dough ball to be slightly smaller than the size of your skillet and top with toppings of choice. For mine, I put a good layer of pizza sauce, a layer of mozzarella cheese, sliced roasted red pepper, a slice or two of prosciutto, and crumbles of goat cheese.
Now for the tricky part. Slide a floured spatula under the dough. Place your peel or baking sheet beside the skillet and slide the pizza into the skillet. This is much easier if you have a buddy who can hold the baking sheet while you slide the pizza. I highly recommend buddies. This takes some practice, so don't be worried if the pizza gets a little misshapen or toppings fall off. It'll happen. It'll still be delicious.
Leave the pizza on the stovetop for about 30 seconds then remove and place directly under the broiler. Leave it there for 1 minute then turn it 180 degrees and leave it for another 1-2 minutes. Once it's browned and bubbly, remove from oven. Leave it in the skillet for a minute or two, then use a spatula to slip it out and serve.