Peel the potatoes, cut them into halves (or smaller), and boil until they're very tender.
Meanwhile, fry the bacon in a skillet until crispy. Once cooked, transfer to a paper towel lined plate.
Preheat oven to 375F.
Prep the remaining ingredients while the potatoes and bacon cook.
Add the butter, cream, garlic, scallions (add most of them but reserve some for topping the potatoes once they're out of the oven if you wish), salt, and pepper to a small saucepan. Warm it over medium heat until the butter melts and the flavors infuse for a few minutes (don't let it boil). Once warm, take it off the heat.
Drain the potatoes and return them to the pot they were cooked in. Add the butter/cream mixture and mash until smooth.
To the pot, add the sour cream, half of the cheddar, and half of the cooked bacon. Stir until combined and transfer to a 9x13 casserole dish and smooth into an even layer.
Top the potatoes with the remaining cheese and bacon. Bake for 30 minutes or until hot and bubbly. If you want the potatoes to brown on top more, feel free to carefully broil it for a few minutes.
Top with remaining scallions if you reserved some, and let it sit for 5 minutes or so prior to serving.