Place the oats and buckwheat groats into a small pan and add the water or milk. Leave to soak for at least 20 minutes. 2 hours soaking will give a much better result or leave overnight in the fridge in preparation for the following morning.
When you are ready to serve, gently heat the oats and buckwheat groats in a low heat. Add a little more liquid if needed so it does not stick to the bottom of the pan.
Once the porridge is warmed, stir through the mashed banana, cinnamon, vanilla bean paste and blackberries.
Serve in a pot or small bowl with a few extra blackberries on top.