Scrub baking potatoes. Pat dry with paper towels. Place on a baking tray and roast in a 375˚F (190˚C) oven for 1 hour 15 minutes.
Remove potatoes from oven. When cool enough to handle, cut off about ½ inch lengthwise from the top of each potato. Carefully scoop out the flesh into a mixing bowl, leaving ½ inch of the perimeter intact.
Add salt, pepper, sour cream, and mustard to the bowl. Mash potatoes until all ingredients are well combined.
Add green onions, reserving a tablespoon for use later. Gently mix to incorporate.
Refill the potato shells with the potato mixture, mounding it slightly. Place each potato on individual oven proof serving dish if desired. Bake for 20 minutes.
In the mean time, pan fry bacon on the stove until crisp. Remove and drain on paper towel.
Remove baked potatoes from oven, sprinkle with shredded cheese. Baked for another 5 minutes to melt the cheese.
Remove twice baked potatoes from oven. Sprinkle with bacon bits and remaining green onions.