Preheat the oven to 400°F. Rinse and dry the potatoes, then lightly coat them with olive oil and salt.  Place the potatoes directly on the oven grates and bake 1 hour. Remove from the oven and let cool slightly.

Meanwhile, in a bowl, combine the butter, sour cream, and Cheddar and Gruyère (or any cheese you prefer).

Cut off the top one-fourth of each potato and scoop out all the insides, being careful not to slice through the bottoms of the potato skin.  Scoop out the tops as well.  Add to the bowl with the butter mixture.  Drizzle in truffle oil.

With a potato masher or mixer, mix until all of the ingredients are fully integrated.  Season with salt and pepper.

Scoop the potato mixture back into the empty potato skins, piling it well above the tops, and place the stuffed potatoes on a sheet pan. (Can sit at room temperature for up to 1 hour).

Preheat the oven to 350°F. Bake the potatoes until heated through, about 20-30 minutes.

If using bacon and chives, sprinkle tops and serve hot.