This dough is surprisingly easy to work with, and you can even shape and cook it into mini- or regular-size bagels, though they will be pretzel-flavored bagels :) For bagels, just make sure to boil bagel-shaped dough for 2 minutes before draining them and baking them at 450°F for about 20 minutes. Pretzels are the most moist and tasty the day they're made, but you can freeze them once they’re cooled, store them in a ziplock bag, and then reheat them in a warm oven if you want to eat them later.
Make the pretzel dough: In the bowl of stand mixer, combine the white rice flour, tapioca starch, brown rice flour, sorghum flour, salt, xanthan gum, and baking powder. Whisk to combine, then fit the stand mixer with the paddle attachment.
Turn out the dough onto one of the prepared baking sheets. Gently punch it down to deflate it, then cut the dough into 12 even pieces and cover them with a sheet of plastic wrap.
Working one at a time and quickly so the dough doesn’t dry out, kneed a piece of dough until completely smooth, then using your hands, roll it on the silicone mat into a long, even rope about 15 inches long. The dough should be moist and slightly sticky. If it’s not, kneed in a half teaspoon of water and roll it out again.
Then, form the dough rope into a into “U" shape.
Gently twist the ends together.
Then firmly press the rope into the bottom of the “U,” ensuring it’s moist enough to adhere to itself. If the dough isn’t staying smooth or is cracking when you shape it, lightly dampen your hands and roll the rope a few more times to coat it in light moisture. Place the shaped dough on the prepared baking sheets.
Prepare the cooking water: Turn off the heat under the boiling water. Slowly add the baking soda and sugar to avoid the baking soda reaction from causing the water to overflow.
Return the water to a rolling boil, then one at a time, boil the pretzels. If the pretzels immediately float, boil for about 10 seconds, then, using a slotted spoon, return them to the prepared baking sheets. If they sinks, wait for them to float to the top of the water, then remove it. (Though if it’s sticking underwater for a while, it may be stuck to the bottom of the pan; you can gently coax it away with your slotted spoon.) Sprinkle the boiled pretzels very generously with pretzel or kosher salt.