Preheat your oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish. Cook your bacon until crispy, drain on paper towels, then crumble it into bite-sized pieces.
Wash and scrub your potatoes thoroughly, then slice them into ¼-inch thick rounds. Keep the sliced potatoes in cold water until ready to use to prevent browning and remove excess starch.
In a large mixing bowl, combine the sour cream, mayonnaise, melted butter, garlic powder, salt, pepper, and paprika if using. Whisk until smooth and well incorporated.
Drain the potato slices and pat them dry. Layer half of the potato slices in the prepared baking dish, slightly overlapping them. Spread half of the creamy sauce over the potatoes, sprinkle with 1 cup of cheese and half of the crumbled bacon. Repeat with the remaining potatoes, sauce, cheese, and bacon. Finish by sprinkling green onions over the top.
Cover the dish with aluminum foil and bake for 40 minutes. Then remove the foil and continue baking for an additional 20-30 minutes, until the potatoes are fork-tender and the top is golden brown with bubbling cheese. For an extra crispy top, broil for the final 2-3 minutes, watching carefully to prevent burning.