Preheat the oven to 170C / 338F and line a baking tray with baking paper
In a large mixing bowl, add all dry ingredients for the buns and mix together, breaking up any lumps in the almond flour.
Add the wet ingredients (boiling water, egg whites and apple cider vinegar) and stir to thoroughly combine into a dough. If it is a little dry, add more water.
With wet hands, shape into 12 small buns (or 8 larger ones) and place on the prepared baking tray, just touching.
Whisk the egg and tablespoon of water for the glaze together and brush over the top.
Score crosses in the top lightly with a knife. Mix together the cross ingredients to form a smooth paste and pipe on top.
Bake for 55 - 60 minutes until a skewer comes out almost clean. I think these are best left a little moist, as it helps them get even crisper when toasting.