Activating the yeast. Combine the yeast, sugar, and warm water in a large bowl and mix gently. Set aside until the mixture has combined and swelled to twice its size, which should take about 15 minutes.
Preheating. Preheat the oven to 200 degrees F.
Combining the dry ingredients. Put the sorghum flour, white rice flour, tapioca flour, and potato starch into the bowl of the stand mixer. Combine. Add the baking soda, salt, and xanthan gum. Combine well.
Adding the liquid ingredients. While the stand mixer is running, add the yeasty water, the egg and apple cider vinegar, and then 3 tablespoons of the olive oil. Allow the mixer to beat these liquids into the dry ingredients on low speed. Pour in the club soda in a slow drizzle. Pour in only as much as is needed to wet all the ingredients completely. The dough should feel soft and firm, like a baby's bottom. Turn off the oven.
Kneading the dough. Attach the dough hook to the mixer and stir the dough on medium speed for 5 minutes. This will give the dough a chance to cohere more evenly. It will also whip air into the dough, which will cut the usual density of gluten-free bread. After 5 minutes, turn off the mixer and transfer the dough to an oiled bowl. (If you do not have a stand mixer, knead the bread by hand on a gluten-free-floured surface for at least 10 minutes.)
Allowing the dough to rise. Put the bowl into the oven, with a damp towel over the top of it. Leave the bowl there for 90 minutes. The dough will not have risen much at this point. There is no gluten to stimulate rising. Accept that.
Baking the pizza dough. Take the bowl out of the oven and turn the oven up to 450 degrees F. Sprinkle a handful of cornmeal onto a pizza tray or a baking sheet. Place the pizza dough onto the tray and start to slowly spread the dough to the outer edges of the tray with your hands. Work gently, with the heel of your hands. When the dough has reached the edges of the tray, smooth the edges with your fingers. Let the dough rest for 20 minutes. Then, sprinkle the remaining olive oil on the surface of the dough. Slide the tray into the oven and bake for 7 minutes, or until the top is browning and the olive oil has been absorbed.
Topping the pizza. Top the pizza with your favorite sauce or vegetables, meats, and cheeses. Slide the tray into the oven again and bake for 10 minutes or so, until the cheese has melted and the sauce is bubbling.
Suggestions. There are, of course, a hundred different ways to top pizza. I'm especially fond of fresh mozzarella, basil, goat cheese, artichoke hearts, and prosciutto. Feel free to play with the flour combinations in this recipe, which is only a guide. I rarely make the same one twice.