Preheat oven to 350 degrees F. Place potatoes and garlic in a lightly greased roasting pan. Cover tightly with foil. Bake 60 minutes or until potatoes are just fork tender. In a medium-sized bowl, blend mustard, butter, and parsley; toss with hot potatoes. Bake, uncovered, an additional 15 minutes or until potatoes are crisp. Serve immediately.