Pre-heat oven to 400 degrees. Spray a large baking sheet with non-stick cooking spray.
Cut the ends of the potatoes off and discard. Cut the rest of the potatoes into 1/2 inch slices.
Brush both sides pf the potato slices with the melted butter and sprinkle with salt and pepper.
Place on baking sheet and bake for 30 to 40 minutes, or until lightly browned. Flip the potato rounds over about halfway through cooking time (15-20 minutes) to brown the other side.
When potato rounds are done, top with cheese, bacon and green onions.
Pop the baking sheet back into the oven for 3-5 minutes, or until the cheese is melted.
Top with a small amount of sour cream, if desired. Serve immediately.