Combine all ingredients. A stand mixer will do this job with ease. The dough doesn't need to be kneaded, though, just well combined. Cover with plastic, and let sit overnight at room temperature.
1 cup organic sorghum flour, 1 cup tapioca flour, ½ cup teff flour, ½ cup millet flour, ⅓ cup organic cornstarch, 1 tablespoon xanthan gum, 2 teaspoons sea salt, ½ teaspoon instant yeast, 1 ½ cup warm water
Stir dough down and shape into a round loaf. Set it in a floured towel, and allow to rise 2 hours.
Preheat oven to 450 F with a cast iron pot and lid inside.
Remove the hot pot from the oven. Gently roll the dough into it. Cover with the hot lid and bake 30 minutes.