Preheat your oven to 375°F and grease a 9x12-inch casserole dish.
In a large Dutch oven, boil the cubed potatoes until they’re fork-tender, about 10-15 minutes. Drain thoroughly and return to the pot.
Add the melted butter and softened cream cheese to the potatoes. Gently mash using a potato masher—don’t over-mix.
Stir in the sour cream and gradually add the heavy cream. Stop adding cream once your potatoes reach a creamy, but thick consistency.
Fold in 5 cups of shredded cheddar cheese, 2 sliced green onions, 10 slices of crumbled bacon, salt, and pepper. Adjust seasoning to taste.
Transfer the mixture to the prepared casserole dish and spread evenly. Top with the remaining cheese.
Bake for 30 minutes, or until the cheese is bubbly and golden.
Remove from the oven and garnish with the remaining green onions and crumbled bacon. Serve warm and dig in!