Whisk together the yeast, water, and 1 tablespoon of the coconut sugar in a small bowl. Allow the yeast to activate for 8 to 10 minutes, or until it smells very fragrant or looks a little bubbly.
Add the dry ingredients (millet flour, brown rice flour, tapioca flour, xanthan gum, sea salt, and baking powder) in a stand mixer fitted with the paddle attachment. Turn the mixer on for a few seconds to mix the flours.
Add the yeast mixture, eggs, olive oil, and cider vinegar to the stand mixer and mix until the dough is combined. Note: the dough will be very sticky and won't resemble regular bread dough.
Transfer the dough to a lightly oiled or greased 9"x5" loaf pan. Smooth into an even layer with a rubber spatula. Cover with plastic wrap and store in a warm spot for 1 hour, or until dough doubles in volume.
When ready to bake, preheat the oven to 350°F. Bake on the center rack of the preheated oven for 30 minutes. Remove from the oven, cover with foil (to avoid the top of the bread burning), and bake another 15 minutes.
Allow bread to cool 10 minutes before releasing it from the loaf pan. Cut into large slices and enjoy!