Preheat oven to 350 degrees. Line a baking sheet with a non-stick mat or parchment paper.
Whisk together the coconut flour, almond flour, tapioca flour, salt, and baking powder in a mixing bowl.
Add the eggs, coconut oil, and hot water and whisk together until very smooth. Let sit for 10 minutes to allow the coconut flour to fully absorb into the liquids.
Place 8 mounds of batter, about 1/4 cup each, evenly spaced on the prepared baking sheet. I use a 2 tablespoon scoop and place two scoops on top of each other. see picture for reference to how the batter should look before it goes in the oven.
Sprinkle the tops of the buns with poppy seeds, dehydrated garlic, or sesame seeds(or all mixed together!) before baking, if desired.
Bake buns for 8-9 minutes, or until set in the center. let cool and store in an airtight container.
Makes 4 buns using 2 pieces for a top and a bottom.