Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish.
In a large bowl, mix sour cream, mayonnaise, ranch seasoning, salt, and pepper.
Add diced potatoes and toss to coat evenly.
Transfer the mixture into the prepared baking dish and spread it out evenly.
Top with shredded cheddar cheese, crumbled bacon, and green onions.
Drizzle with melted butter.
Cover with foil and bake for 45 minutes.
Remove foil and bake an additional 15-20 minutes, or until potatoes are tender and top is golden brown.
Serve warm and enjoy!