After much experimentation, I have come up with a gluten free pizza mix recipe that really seems to work well! It's based on a modified version of FioreGlut gluten free flour. It's got much the same ingredients, but I've added a few small tweaks.
You will need:
-- a sturdy and durable pizza stone or some other similar cooking device (such as unglazed quarry tiles) for your oven
-- a pizza peel
1 1/4 cups corn starch
1 1/4 cups white rice flour
1/2 cup potato starch
1/4 cup tapioca starch
1/4 cup soy flour
1 Tbsp dry milk powder
1 1/2 tsp xanthan gum
1 1/2 tsp salt
1 1/2 tsp active dry yeast
1 tsp inulin
1 tsp baking powder
2 cups very warm water
2 Tbsp olive oil, plus some for drizzling over pizza
Mix dry ingredients (except for the yeast) in your stand mixer's bowl. Dissolve yeast in the water for approximately 5-10 minutes, then add oil to the water/yeast mixture.
Add the wet ingredients to the dry ingredients and mix on medium for approximately 3-4 minutes or until dough is thoroughly mixed. The dough should have a consistency a little bit similar to ice cream. You should be able to "dollop" it with a spoon, not pour it. If it's too wet, make sure to mix in some more white rice flour until it's solidified enough. On the other hand, you don't want it so dry that it forms a nice dry dough ball like a normal gluten pizza dough would be--if it's too dry, it'll dry out when baking in the oven.
Cover and let rise in a warm location for approximately an hour or so, then place in fridge to rise overnight. I transfer my dough to a tupperware container for this step--if you do too, make sure you scrape the mixing bowl, don't leave any dough behind!
(NOTE: You can skip the fridge rise if you're really hungry, but the pizza won't taste quite as good, and the crust won't wind up being as well developed.)
The next day, when you're ready to make pizza, place your pizza stone in the oven as low as you can get it (I have mine an inch off the oven floor) and preheat to as high as it'll go (I used the calibration setting on my oven to get up to 530 degrees) for approximately 30 minutes. Make sure you've got a sturdy, durable stone--I had a thin one that broke in half on the first try. Near the end of the preheating time, get your cheese, sauce, and toppings ready, and get your pizza peel well floured with GF flour (don't skimp on the flour).
Place approximately a third of the dough on the peel and roll it around in the flour until you get a nice dry, smooth ball that doesn't stick to the peel or your hands. Then GENTLY AND SLOWLY press the ball into a small disc. As you press it out, you may need to periodically add a bit of flour to the peel, the underside of the disc, or the top side of the disc--throughout this process, stickiness will be your main enemy. Don't rush--you might tear the dough.
Keep pressing the disc outwards a tiny bit at a time. After it's gotten thin enough, you can gently place your palm on one edge of the disc, and tilt the peel slightly toward the opposite side in order to stretch it out using gravity. Keep moving your hand around the disc and rotate the direction of tilt in order to evenly stretch out the disc until it's your desired diameter (I like mine very thin, at around 14"-16"). Watch out that you don't tear it! And keep shuffling the peel every now and then to make sure the disc moves freely on the peel.
Once that's done, take a fork and gently poke the disc in a variety of places to give it breathability, then try to brush the excess flour off the peel into your kitchen sink or wherever (if you skip this step, you will wind up having to silence the smoke alarm when you get a bunch of flour burning up into smoke in your oven!). Then slide the naked dough off the peel onto your pizza stone in the oven.
Let it sit there around 2 minutes or so to firm up the bottom crust, then carefully use your peel to retrieve the pizza. Add your sauce, cheese, and desired toppings, then drizzle olive oil over the pizza in a spiral fashion. Put the pizza back on the stone in the oven, and bake until cheese is fully melted.
YIELD: Approximately three 12" pizzas. I stretch mine very thin, and am able to get one 14"-15" pizza, plus two 13" pizzas.
If anyone wants to try this with a high-temp oven (Blackstone, wood fired, etc), I'd be curious to know what your results are!