Add the flours, starches, xanthan, egg white powder, sugar and salt to the bowl of a stand mixer fitted with the paddle attachment and mix well. Add the yeast and stir again.
Beat the eggs, warm water and oil together in a bowl until smooth. Pour into the flour mixture and beat on low until it is incorporated. Beat on high for 2 minutes until the dough is light and fluffy. It will be very sticky.
Spray a medium bowl with gluten-free cooking spray or wipe with oil. Add the dough, cover with plastic and place in the fridge to rise for 3 hours.
When ready to bake preheat the oven to 500 degrees. If you have a pizza stone, it should be on the bottom shelf.
Divide dough in half. Turn one portion out onto a piece of parchment paper. Using damp hands shape dough into a 9-inch circle, re-dampening your hands as necessary. Shape dough so that it is relatively thin in the middle and thicker around the edges, taking care to create a nice, smooth lip on the edge of the dough. Cut off any excess parchment paper.
Slide dough on the parchment directly onto the pizza stone. If you don’t have a pizza stone, place on a baking sheet in the oven. Let the dough cook for about 5 minutes, then using tongs, carefully lift the edge of the crust and remove the parchment paper. Continue cooking the dough for about 5 minutes more, or until it is lightly golden brown. While the first crust is baking shape the second crust as directed above.
Remove from the oven and bake second crust. Top each pizza as desired (NOTE: fresh mozzarella makes gluten-free pizza crusts quite soggy, so it’s best to use the shreddable kind). Drizzle some olive oil around the edge of the crust and return the each pizza to stone to finish baking until the cheese is melted and the toppings are hot and sizzling, 5-10 more minutes.