1. Preheat an oven to 200 degrees Celsius, or equivalent. Wrap the potatoes in foil and thread them onto a metal skewer, if you have one. Bake for 50-60 minutes depending on the size of your spud. Once it’s well cooked, remove from the oven and leave to cool slightly.
2. Cut each potato in half horizontally and scoop out the fluffy centre, keeping the outer shells as intact as possible. Mash the potatoes with the milk and a tablespoon of butter. Lay the potato shells on a baking tray.
3. Destem the kale and chop it finely. Add a tablespoon of butter to a large frying pan and add the kale along with a little splash of water. Sauté till wilted and bright green. Add the spring onion and cook for a further minute before folding this through the mashed potato, along with half the cheese. Season with salt and pepper.
4. Fill each potato shell with the colcannon. Top with the remaining grated cheese. At this point you can leave it to cool and place on the fridge or freezer, or else return the tray to the oven till the cheese is golden and bubbling, 15-20 minutes.