Wash the potatoes well, add a sprig of mint into the water with a big pinch of salt.
When the water is boiling, tip in the potatoes ,cover and boil until they are cooked.Drain and leave to sit in the dry saucepan with the lid on with the heat off (obviously) if you need to let them sit for a few mins.They can sit like this for half an hour easily.
When ready to serve, put them into a bowl with few knobs of butter on top and some sea salt.