Wash and cut your rhubarb into 1cm slices and soak them in a bowl of water for 20 minutes. Drain off the water and sprinkle the rhubarb with Cornish Sea Salt Crystals. Leave for a further 20 minutes to draw out some of the water. Place in a small saucepan and cook for 7-10 minutes on a low heat.
Mash into a paste with a fork and keep in a sterilised jar.
For a fermented version, instead sprinkle the rhubarb with 2% weight of Cornish Sea Salt Crystals then leave overnight in a bowl for the moisture to be drawn out. Transfer to a sterilised jar with a muslin/cheesecloth lid and allow to ferment for 10-14 days. Seal the jar and keep in a cool place.