Preheat the oven to 400ºF / 200ºC degrees and line a baking sheet with parchment paper.
Rub the potatoes with the oil and lay on the baking sheet.
Bake for one hour until tender.
Remove from the oven and turn the temperature down to 350ºF / 180ºC degrees.
Peel the skins from the potatoes and chop into chunks. Place into a large mixing bowl then add in the cream cheese, shredded cheddar, heavy whipping cream, butter and salt.
Transfer to a baking dish and bake in the oven for 20 to 25 minutes until hot and the cheese is melted.
Add the crispy onions and bake for a final five minutes then serve.