Mix together flours and water to begin a process bakers call “autolyse”. Starter can be mixed in at this stage or added after autolyse. Adding starter at the beginning allows it to incorporate more easily and jumpstart fermentation, delaying the addition of starter until after autolyse helps better gluten and dough development to take place.
Autolyse 20-60 minutes.
Add salt and some of the additional water to dissolve salt and help incorporate into dough. (Add starter if you have not added it yet)
Cover bowl and let dough ferment 3-6 hours at room temperature or 24-48 hours in the fridge. Do 2-4 stretches and folds during the first 2 hours of fermentation.
Remove dough from bowl to a smooth, clean, unfloured surface.
Cut square sheets of parchment, drizzle with avocado oil, rub oil all over sheets and on hands. Use dough scraper to cut sections of dough from the fermented sourdough. Place on oiled parchment. Like playing a piano, use fingertips to gently dimple into the dough with slight spreading of fingertips to shape the dough. Do not pull, tear, roll, or stretch the dough by force as this will make air escape and result in a denser crust. If dough resists, allow it to rest a few minutes before shaping again. Shape until about ½ inch thick.
Optional, but recommended, let your oiled preshaped pizza dough rest for 30 minutes to 3 hours. After optional rest, do a final shaping of the crust by oiling fingertips and gently dimply and spreading dough. Be careful not to tear or press out air at this point.
Top pizza as desired. Transfer pizza with parchment underneath onto the hot baking steel or stone.
Preheat oven with a baking steel or baking stone (a cookie sheet can work in a pinch) inside to 550 degrees F.
Bake 3-8 minutes, until toppings are cooked and crust is beginning to turn golden brown. Turn on broil for 1-2 minutes until baked to your level of doneness (lightly golden, or more dark crust with singed pepperonis). Check the bottom of the crust for doneness as well. Remove with a pizza peel.
Cool 5 minutes before cutting.