Wash and scrub the potatoes. Make thin slices about 1/8-inch apart, cutting almost all the way through the potatoes, but leaving the bottom intact. You can place the potatoes between two wooden spoons to prevent cutting all the way through.
Brush the potatoes with melted butter and season with salt, pepper, and nutmeg (if using).
In a small bowl, whisk together the heavy cream and minced garlic.
Place the potatoes in a baking dish. Pour the cream mixture around the potatoes.
Sprinkle Parmesan cheese over the top of the potatoes.
Bake for 45-60 minutes, or until the potatoes are tender and golden brown, and the cream has thickened. If the top starts to brown too quickly, you can loosely tent it with foil.