1
Preheat an oven to 350°. Grease one 9x13-inch baking pan with butter. Spread potatoes evenly in the pan.
2
Whisk together heavy cream, milk, garlic, flour, salt, and pepper in a large bowl.
3
Pour cream mixture over the potatoes.
5
Bake for 20 minutes, then remove the foil.
6
Continue baking until potatoes are easily pierced with a fork, about 40 minutes.
7
Remove potatoes from the oven and sprinkle Cheddar cheese on top.
8
Return to oven and bake until the cheese is melted, 5 to 10 minutes.