Pre-heat your oven in broil mode (or grill) to 400ºF (200ºC).
Place potatoes in a large pot of salted water. Bring the pot to a boil and cook, covered for 30-35 minutes or until they are fork-tender. Drain well and set aside.
Lightly grease a large baking sheet with a teaspoon of oil or oil spray. Arrange the cooked potatoes onto the baking sheet and use a potato masher to lightly flatten the potatoes in one piece. Do not push too hard, or potatoes will end up completely mashed.
In a medium bowl, mix the butter, salt, pepper, minced garlic, parmesan, and Italian seasoning. Pour the mixture generously over each potato using a tablespoon.
Transfer the baking sheet with potatoes to the oven and broil (or grill) until potatoes are golden and crispy – about 10-15 minutes. Serve the garlic butter parmesan smashed potatoes with parsley and more parmesan, if you like.
