Preheat your cast iron skillet in the oven at 425 degrees F.
Once the pans are scorching hot and fully preheated, take them out of the oven.
Drizzle some olive oil in your skillet.
Ladle your sourdough starter into the skillet as evenly as you can. There isn't an amount for this, you just spread it out until you have a nice thin layer in the size you want.
Drizzle more olive oil over top.
Sprinkle with salt and pepper (and Italian seasoning if you want, I just add that to my tomato sauce so I don't add it here also).
It will already start to bake when it makes contact with the pan.
Stick it back in the oven, until crispy, and easily pulls up from the pan. About 10 minutes.
Take it back out, and add your tomato sauce, cheese, and other toppings.
Then put it back in the oven until the cheese is melted.