Preheat oven to 375°F (190°C) and grease a baking dish.
In a large mixing bowl, combine cooked potatoes, shredded cheddar cheese, sour cream, heavy cream, melted butter, chopped onions, salt, black pepper, garlic powder, and paprika. Mix well.
Transfer the mixture to the prepared baking dish and spread evenly.
Sprinkle crushed Ritz crackers over the top for a crispy topping.
Bake for 25-30 minutes or until golden brown and bubbly.
Remove from the oven, let it cool for a few minutes, and serve warm.