Preheat your oven to 400°F (200°C).
Wash and scrub the russet potatoes thoroughly.
Pierce each potato with a fork to allow steam to escape.
Place the potatoes directly on the oven rack and bake for 45-60 minutes until tender.
Remove the potatoes from the oven and let them cool slightly.
Once cool enough to handle, slice each potato in half lengthwise.
Carefully scoop out the inside of the potatoes into a mixing bowl, leaving a thin layer of potato on the skin.
Add butter, sour cream, milk, cheese, salt, and pepper to the bowl with the scooped potato.
Mix until smooth and creamy, then fold in green onions.
Stuff the potato skins with the creamy mixture and top with additional cheese, if desired.
Return the stuffed potatoes to the oven and bake for an additional 15-20 minutes until golden brown.