Preheat the oven to 200°C.
Scrub and pat dry the potatoes then pierce them with a fork and rub their skins with olive oil.
Place the potatoes on a baking sheet. Season with salt and pepper.
Bake for about 1 hour, until the potatoes are tender .
Let the potatoes cool, then cut them half lengthwise. Using a spoon, scoop out the potato flesh, making sure the skin doesn’t tear (hold the potato in your palm).
Place skins, skin side down, on an oiled baking sheet. Brush the inside of them with some olive oil then sprinkle salt and pepper over them. Bake for another 8-10 minutes until crispy and golden.
Meanwhile mix the scooped potato flesh with most of the cheese and the sour cream. Add the chives and season with salt and pepper.
Fill the crispy potato skins with the mixture, sprinkle the reaming cheese on the top and grill the potatoes for 5-10 minutes in the oven until the cheese has melted and lightly browned.