Heat the oven to 200C/fan 180C/gas mark 6. Rinse the potatoes in cold water, pat them dry with kitchen roll and then prick the skins all over with a fork.   Rub them lightly with olive oil and then bake directly on the shelf in the oven for 1 hour.    They might need a bit longer (15 to 30 minutes) if the potatoes are much bigger than 270g each in weight.

Meanwhile, melt the butter in a small saucepan over a medium heat. Add the spring onions and cook them for 2 minutes, until soft, stirring frequently.

When the potatoes are baked, remove them from the oven and cut them in half horizontally and scoop out the flesh. Place the potato skins on a baking tray and the flesh into a large bowl.

Mash the potato with the crème fraiche and then stir in the spring onions and grated cheese until well combined. Pile the potato mixture back into the skins and then return them to the oven to reheat for 10 minutes.

Enjoy as a side dish or as lunch or a snack with some salad leaves.