Preheat your oven to 400°
Wash and dry the potatoes and rub with olive oil
Place on a sheet pan and sprinkle with kosher salt
Poke potatoes with a fork (or knife) to allow some vents
Put in the oven and bake until done, about 35 min to an hour depending on size of the potatoes
Once the potatoes are done (check with a skewer) remove them from the oven and let them cool a bit
Once they are cool enough to handle, slice the potatoes in half lengthwise creating two "boats"
Carefully scoop out the flesh of the potato halves, leaving a small ridge along the sides and bottom (like for potato skins).
Put all of the scooped out potato in a bowl or pot, so you can mash them
Mash the potatoes with a hand masher at first, then add your butter, cream (or milk) and salt and pepper.
Whip the potatoes with your hand masher or electric beater to remove as many lumps as you can. Creating a creamy mashed potato.
Once they are mashed, add your cheese and stir it through. Feel free to add extra cheese if you want them really cheesy.
If using bacon, add it now as well. Taste and adjust seasoning if needed.
Fill each half shell with a generous scoop of the mashed potatoes
Return to the oven and bake for a further 10 minutes to create a bit of a crust and some golden brown color on your potoates.
Serve with sour cream and whatever other toppings you like.