Put oven rack in upper third of oven and preheat oven to 425°F.
Peel potatoes and slice 1/8 inch thick, then toss with cream, garlic, salt, and pepper in skillet. Cover with foil and roast until potatoes are very tender, about 25 minutes. Remove from oven and preheat broiler. Remove foil and sprinkle potatoes with cheese. Broil until top is browned, 2 to 3 minutes.