Preheat the oven to 200C/400F degrees and line a baking sheet with parchment paper.
In a medium mixing bowl, add the oat fiber, psyllium husk powder, baking powder and spices and whisk together.
In another medium mixing bowl beat the eggs.
Add the Greek yogurt and continue to whisk until smooth.
Pour in the butter and vanilla and mix.
Add the dry ingredients to the wet mixture and stir until combined.
Sprinkle the apple cider over the dough and work it through..
Pour the hot water over the dough, mix it through and let it sit for 10 minutes.
Cut the mixture into 6 and make the dough into 6 buns/.
Place the buns on a baking tray and brush them with melted butter.
Bake for 10 minutes then turn the oven down to 180C/350F degrees and bake for a further 20 minutes until the buns are firm and golden.
Remove from the oven and allow to cool before decorating them.
To decorate ours we mixed Greek yogurt with powdered sweetener into a paste. You could use cream cheese too.