Preheat the oven to 180C/350F degrees.
Grease and line a 2lb loaf tin with parchment paper (if you have a 1lb tin you could reduce the ingredients OR, bake some rolls with any left over dough).
In a bowl, add the almond flour, baking powder, salt and psyllium husk power. Mix well.
In another bowl, mix the egg yolks and melted butter together (I use a whisk)
Add this mixture to the dry ingredients and stir well.
Add the apple cider vinegar and stir thoroughly.
In another bowl, whisk the egg whites until stiff. Fold them into the bread mixture.
Add the boiling water, ¼ cup at a time until you have a light dough. (You may not need all the water so add a bit at a time to prevent a soggy dough).
Bake for 30 minutes until firm.