In a large pot, cover the cubed potatoes with cold water. Add salt and bring to a boil. Cook for 15-20 minutes or until fork-tender.
Meanwhile, cook the bacon until the fat is completely rendered. Cool and chop. Save for final steps.
Drain the potatoes and pass them through a potato ricer (or mash until smooth). Transfer to a large mixing bowl.
Add the heavy cream, melted butter, chopped bacon, scallions, and 1 cup of shredded cheddar cheese to the potatoes. Mix until fully combined.
Taste and adjust seasoning with additional salt, being careful not to over-salt.
Transfer the potato mixture to a baking dish. Top with the remaining 1 cup of shredded cheddar cheese.
Bake in a preheated oven at 350°F until the casserole is heated through and the cheese on top is melted and bubbly, about 15-20 minutes.
Serve hot, generously drizzled with gravy, alongside turkey, stuffing, and your favorite Thanksgiving sides!