Twice Baked Potato Casserole

Preheat oven to 400°F. Lightly grease a 2-quart baking dish with cooking spray, and set aside. Rub potatoes with oil, 1 teaspoon of the salt, and 1/2 teaspoon of the pepper. Pierce all over with a fork, and place on an aluminum foil-lined baking sheet. Bake in preheated oven until tender, about 1 hour. Cool slightly, about 10 minutes. 

Cut potatoes in half lengthwise, and scoop out flesh into a large bowl. Chop enough of the potato skins into 1-inch pieces to equal 1 cup. Discard remaining skins or reserve for another use. Gradually add butter to potatoes, mashing with a potato masher until incorporated. Fold in half-and-half and sour cream until mostly smooth. Fold in 1/2 cup of the chopped potato skins, 1/2 cup of the bacon, 2 tablespoons of the chives, and remaining 1 teaspoon salt and 1/4 teaspoon pepper. Transfer potato mixture to prepared baking dish. Sprinkle top evenly with cheese and remaining 1/2 cup chopped potato skins. 

Bake in preheated oven until golden and bubbly, about 20 minutes. Sprinkle top with remaining 1/2 cup bacon and 1 tablespoon chives, and serve hot.