Preheat oven to 170 degrees F and turn off. The bread will rise in the warmed oven before baking.
Make sure the dry ingredients and eggs have come to room temperature. Combine the flours, xanthan gum, salt and baking powder in a large bowl.
In the medium bowl, separate the egg whites from the yolks (use the yolks for another recipe like breakfast tacos). Transfer the egg whites to a stand mixer. Whisk on high speed for about 3-5 minutes until the eggs have stiffened.
Meanwhile, add the water, olive oil and honey to a 2-cup Pyrex measuring cup. Heat in the microwave for about a minute. Mix well then determine the temperature with a candy thermometer. It should be about 110-115 degrees F. When the proper temperature is achieved, stir in the yeast. Let it proof for about 5 minutes.
Add the apple cider vinegar and yeast mixture to the egg whites. Whisk gently for a few seconds. Add the dry ingredients. Whisk slowly at first then scrape down the sides. Beat at medium high speed for 4-5 minutes.
With wet hands scoop up some of the dough and allocate into each pan.
For the 8×4 loaves, let the bread rise in the oven for about 1 hour. Turn the heat up to 350 and bake for 60-70 minutes.
For the hamburger buns and mini loaves, place in the oven and let rise for about 45 minutes. Turn the heat up to 350 degrees and bake for about 30-40 minutes. The bread should be brown and crusty.
Promptly remove from the baking apparatus and let cool completely on a cooling rack before cutting (if still warm the bread might deflate).
Use a serrated bread knife or electronic knife to cut the bread. Store in the freezer until ready to use.
When ready to use, either toast the frozen bread in a gluten-free designated toaster or under the oven broiler for a few minutes.