Preheat oven to 350F. If you are making a loaf, grease a 9x5 inch loaf pan well. If you are making rolls, line a large cookie sheet with parchment paper or a silicone liner.
In a large bowl, whisk together the coconut flour, almond flour, psyllium husk powder, baking powder, and salt.
Stir in egg whites, oil and apple cider vinegar. Slowly pour hot water over, stirring until dough expands. Start with the lesser amount and add a bit more until dough seems like it has expanded about 1.5 to 2 times. Do not add too much water or it can become a gloppy mess.
For a loaf of bread, shape into a rough rectangle and place in prepared baking pan. Bake 60 to 75 minutes, until browned and crust feels hard to the touch (it will look done long before it really is. Don't take it out early or it will deflate). Remove and let cool in pan.
Divide dough into 10 to 12 equal pieces and roll between palms into a rough ball. If dough is sticky, oil your palms with olive or avocado oil. Place on prepared cookie sheet. If you want flatter rolls for burgers or sandwich rolls, press down to 1 inch thickness with your palm.
Bake 45 to 60 minutes, depending on size and shape of rolls. Rolls should be well browned and quite firm to the touch. Remove and let cool on pan.