Preheat the oven to 350F; line a baking sheet with parchment paper or a silpat liner.
Whisk together the almond flour, coconut flour, psyllium husk powder, salt, and baking powder in a large bowl.
Stir together the dissolved beef gelatin, egg whites, vinegar, and stevia in a small bowl.
Add the egg white mixture, melted ghee, and boiling water to the dry ingredients, and beat with a handheld electric mixer until it forms a dough.
Let the dough rest 3 minutes, and then divide it into 4 equal portions. Roll each into a ball (dampen your hands slightly with water to help prevent the dough from sticking to you; don't use oil or your bread may brown too much). Arrange the balls on the prepared baking sheet. Sprinkle the sesame seeds on top.
Bake until the rolls are golden on the bottom and have formed a hard outer crust, about 25 to 30 minutes. Like a loaf of regular bread, these buns should sound hollow when you tap the bottom.