Preheat the oven to 375°F (190°C) and line a baking sheet with parchment paper.
Mix dry ingredients – In a large bowl, whisk together oat flour, almond flour, tapioca starch, baking soda, salt, and xanthan gum.
Combine wet ingredients – In a separate bowl, whisk buttermilk, egg, melted butter, and honey.
Form the dough – Gradually add the wet ingredients to the dry ingredients, stirring gently until a sticky dough forms.
Shape the loaf – Lightly flour your hands, shape the dough into a round loaf, and place it on the baking sheet.
Score the top – Cut a deep cross on the top with a sharp knife to help the bread bake evenly.
Bake for 35-40 minutes, or until golden brown and a toothpick inserted in the center comes out clean.
Cool before slicing – Let the bread rest for at least 15 minutes before slicing for the best texture.