Set each potato in to a large spoon and make thin slices along the length of the potato, using the spoon as a guide so as not to cut all the way through the potato.
Preheat oven to 400 F.
Pour the olive oil in to a large bowl or container. Toss the potatoes liberally in the olive oil, making sure to get it in between the slices. Arrange the potatoes on a foil lined baking sheet, cut side up. Sprinkle with salt and pepper to taste, making sure to season in between the slices.
Bake for 30 minutes until the edges begin to turn golden brown. Remove the potatoes, sprinkle with cheese, and bake for another 15-20 minutes until fully tender and golden brown.
Sprinkle with fresh chives and serve with sour cream.