simple potato gratin

INGREDIENTS

• 3 tablespoons butter, cut into pieces, plus an additional pat for buttering gratin dish
• 4 large yellow potatoes* (about 1 1/2 pounds), peeled
• Salt and freshly ground black pepper
• 1 cup milk, half-and-half or cream (if using something richer than milk, you can skip the butter)
• 2 ounces cheese, grated or crumbled (Parmesan or Gruyere are the classics, but that doesn’t mean that goat cheese, blue cheese or any of your favorites won’t work as well) [optional]