Add the yeast and granulated sugar to the bowl of a stand mixer. Slowly pour in the milk, making sure the yeast is moistened. Let sit for at least 15 minutes to "bloom" as you prepare the other ingredients.
Add the white rice flour, brown rice flour, arrowroot, tapioca flour, sorghum flour, xanthan gum, baking powder, and salt to medium bowl. Whisk well to combine.
When the yeast has bloomed, add the honey, egg, and avocado oil. Use the paddle attachment to mix on medium low speed until combined.
Add the flour mixture and mix on low until combined. Stop the mixer and scrape down the bowl. Then mix on medium speed for 1 minute.
Use a spatula to scrape down the bowl and form the dough into a ball. Transfer to a lightly floured surface.