Cut in half lengthwise. Scoop most of the potato out of each half, leaving a thin layer next to the skin. Place in large mixing bowl and mash the chunks of potato. Add sour cream, butter, shredded cheddar, garlic powder, bacon, green onions, salt and pepper to potatoes and mash together until creamy. Add more salt or pepper to taste. Scoop the filling into each potato half, dividing evenly and mounding generously. Place onto baking sheet. Add a few sprinkles of shredded cheddar, green onion, and bacon, if desired.