Preheat the oven to 400 degrees.
Wash the potatoes then poke holes throughout the potato with a fork or knife. Place into the oven and bake for 60 minutes, or until cooked through. Remove from the oven and let them cool.
While the potatoes are baking, make the caramelized onions. Place the oil into a skillet over medium heat. Add the sliced onions and cook, stirring often, for 25-30 minutes, or until caramelized and golden brown. Side Note: If the skillet gets dry, add a tablespoon of water or two. Season with sea salt, to taste, and a splash of vinegar. Remove from the skillet and set aside.
When potatoes are done cooking, allow to cool for about 10 minutes. Slice potatoes in half lengthwise and gently scoop out the flesh into a mixing bowl (set skins aside). Add sour cream, butter, sea salt and freshly cracked pepper, to taste. Mix thoroughly then spoon mixture into the potato skins. Top each potato with the caramelized onions then sprinkle the top with a bit of shredded Swiss cheese. Place them back into the oven for a few minutes until the cheese has melted. Serve immediately. Enjoy.