Preheat oven to 425°F.

Clean potatoes in cold water to remove any excess dirt.

Using a fork, poke a few small holes in each potato.

Rub potatoes with the olive oil to coat completely.

Place potatoes on a cooking sheet.

Sprinkle with 1 tablespoon kosher salt.

Place potatoes in preheated oven and bake for 1 hour, until a knife slides easily into the center of each potato.

Remove from oven and allow potatoes to cool to about room temperature. (Up to here can be done up to a day in advance. Store potatoes, covered, in the refrigerator, until ready to use. Allow potatoes to warm to about room temperature before using.)

Create an oval incision just through the skin on top of each potato and gently remove the skin from inside the oval.

Cut 1/2 inch squares through the flesh of the potato. Carefully scoop out flesh, being careful not to break the skin.

Place chunks of potato from all potatoes in stainless mixing bowl.

Add the sour cream, heavy cream, chives, truffle oil and 3/4 cup Parmesan cheese to the bowl.

Season with salt and black pepper, to taste.

Very gently stir the mixture until just combined. Do not over mix - This can make the potato mixture pasty.

Spoon the mixture back in the potatoes, packing it in loosely. (The texture should be loose and resemble a dry potato salad.)

Sprinkle tops of potatoes with 1/4 cup Parmesan cheese.

Dot each potato evenly with cubes of the butter. (Up to here can also be done up to a day in advance. Store the potatoes, covered, in the refrigerator until ready to use. Allow potatoes to warm to about room temperature before cooking.)

When ready to serve, Preheat oven to 425°F.

Carefully place potatoes on a cooking sheet.

Place in preheated oven and bake for 15 minutes, until hot in the center and golden brown on top.

Serve hot.