In a medium bowl, mix the coconut flour, flaxseed meal, psyllium husk powder, salt, baking powder and xanthan gum.
Pour in the melted butter and mix to resemble bread crumbs.
Add the Greek yogurt and stir well.
Add the apple cider vinegar and mix well.
Add the boiling water a ¼ cup at a time until a wet dough forms.
Allow the dough to rest for 10 minutes to firm up.
Preheat the oven to 180C/350F degrees.
Line a baking tray with parchment paper.
Using damp wet hands, split the dough into 4 sections and form them into 4 buns.
Place the bus on the tray and bake for 25 minutes until golden on top.
Turn off the oven and allow to cool for a further 10 minutes.
Remove from the oven and cool thoroughly.