Arrange a rack in the middle position of the oven and preheat to 425-degrees.
Position one potato in between two wooden spoons. Cut vertical slits (⅛ inch apart) in the potatoes, cutting straight down until your knife hits the wooden spoon, leaving the bottom intact. Repeat this cutting process for the remaining potatoes.
Place the potatoes on an unlined baking dish. Use a basting brush to coat about half the melted butter all over the potatoes, including the insides of the slits. Season the potatoes with salt and pepper.
Bake for 30 minutes. After the potatoes have baked for 30 minutes, use a knife to gently pull the layers apart. Brush on the remaining melted butter. Bake 30-35 more minutes, or until the potatoes are crispy on the outside and tender on the inside. (Cooking times may vary depending on the size of the potatoes you are using.)
Top with salt, pepper, parsley and Parmesan cheese, to taste.
Only potatoes grown in Idaho can be called Idaho® potatoes. Idaho’s ideal growing conditions – the rich, volcanic soil, climate and irrigation – are what differentiate Idaho® potatoes from potatoes grown in other states.