Drizzle 1 1/2 tablespoons of the vegetable oil over the potatoes' skins. Massage the oil into the skins. Pierce the surface of the potatoes with a fork to allow steam to escape while they bake.
Slice off the tip of the garlic (the end without the hairy root), then nestle it into the smaller piece of foil. Pour the remaining vegetable oil over the garlic and close the pouch of foil.
Bake the potatoes for 45 minutes-1 hour, or until a knife inserted into the largest potato meets little, to no, resistance.
Once the potatoes have finished baking, cover the sheet pan with a kitchen towel and allow the trapped moisture to steam the skins of the potatoes for 10 minutes. Carefully peel the skins from the potatoes. Discard the skins.
Reduce the oven's temperature to 170°F (or set to "Warm").
Place the peeled potatoes into a large mixing bowl. Unwrap the head of garlic, and squeeze the soft pulp into the bowl with the potatoes by pressing on the stem end.