Wash potatoes and cut into 3/4 inch slices, discarding stem ends.

Place slices in a pot of boiling salted water. Reduce heat to medium and cover pot. Cook potatoes for 20 minutes or until easily pierced with a fork but still firm enough to hold together. Remove slices to paper towels and pat dry.

Place slices on a sprayed baking pan. Gently mash the center of each slice with the tines of a fork.

Melt butter and add garlic and parsley. Brush or spoon over potatoes. Season with salt and pepper.

Bake at 425 for 25 minutes. Top with Parmesan and return to oven to melt cheese, 4-5 minutes. Garnish with rosemary and serve.