Trim ends off sweet potatoes and cut into 1 1/2 inch thick slices. Place in pot of salted water and boil, uncovered, for 20-25 minutes or until fork tender. Drain well.
Preheat oven to broil setting.
Lightly grease a baking sheet with cooking spray. Arrange potatoes on sheet and gently flatten each piece being careful not to break or mash. Mix together butter, garlic and parsley. Pour over each potatoe. Season with salt and pepper and spray with cooking oil. Broil until golden and crispy (about 15 minutes). Remove from oven, sprinkle with parmesan and return to oven until cheese is melted. Season with parsley and serve immediately