Preheat the oven to 375°F.
Bring a large pot of water to a boil. Once the water is boiling, salt the water generously.
Boil the potatoes and peeled garlic cloves until fork tender.
4 Russet potatoes, 3 cloves Garlic
Cut the bacon into small strips (lardons). Place the bacon in a cold pan, and turn the heat on to medium. Crisp the bacon, and drain on a paper towel. Set aside.
4 strips Thick-cut bacon
Add the half and half cream and garlic butter to a sauce pan over medium-low heat. Let the cream mixture heat through, and turn the heat to the lowest setting to keep warm while the potatoes cook.
1 cup Half and half cream, 2 tablespoon Garlic butter
Once the potatoes are boiled, drain them and return them to the pot over medium heat. Let any residual liquid evaporate off the potatoes. You want the potatoes to be completely dry.
Once the potatoes are dry, mash the potatoes with a potato masher to get rid of the majority of lumps.
Pour half of the cream mixture into the mashed potatoes. Fold in with a wooden spoon or a rubber spatula until smooth, and add the remaining cream. Fold in the remaining cream again. Mix in the sour cream and half of the shredded cheddar cheese. Taste for salt, and add as needed.
1 cup Sharp cheddar cheese, ⅓ cup Sour cream, Salt
Transfer the mashed potato mixture to a baking dish, and top with the remaining cheese and crisped bacon. Bake for 15 minutes at 375°F, and broil on LO for another 2-3 minutes. Finish with chopped green onions.
2 stalks Scallions