Preheat your oven to 400°F.
Wash and scrub the potatoes thoroughly, then poke several holes in each potato with a fork.
Rub the potatoes with olive oil and sprinkle with salt.
Place them directly on the oven rack and bake for about 45-60 minutes, or until tender when pierced with a fork.
Once the potatoes are done, remove them from the oven and let them cool for about 10 minutes.
Cut each potato in half lengthwise and scoop out the insides into a mixing bowl, leaving a small border of potato in the skins.
To the bowl with the scooped potato, add Boursin cheese, sour cream, milk, half of the cheddar cheese, chives, salt, and pepper. Mash everything together until smooth and creamy.
Spoon the potato mixture back into the potato skins, mounding it slightly on top.
Sprinkle the remaining cheddar cheese over the filled potatoes.
Place the stuffed potatoes back on a baking sheet.
Return the potatoes to the oven and bake for an additional 15-20 minutes, or until the tops are golden and bubbly.
Let the potatoes cool for a few minutes before serving. Enjoy!