Preheat your oven to 425 degrees. Place your cast iron skillet inside the oven to preheat as well.
Once your cast iron skillet has preheated, remove it from the oven. Coat the bottom with avocado oil.
Scoop 2-3 ladles of sourdough starter into your cast iron skillet, making sure to spread the starter evenly on the pan. The starter may start to cook once you drop it onto the skillet-this is okay!
Sprinkle basil, oregano, salt, pepper and garlic powder onto the top of your dough. Drizzle additional avocado oil and bake in the oven for ten minutes.
Remove from oven and spread a layer of tomato sauce onto your pizza. Sprinkle mozzarella cheese on top and bake for an additional ten minutes.
Remove from oven and let cool before serving.