Stir together sugar and milk in a medium saucepan, bring to a boil whisking occasionally. Boil for 3 minutes. Remove from heat and quickly stir in peanut butter and marshmallow creme. Pour into a buttered foil-lined 8 or 9 inch baking dish. Let cool on counter or fridge (depending on your time). Lift out with foil and use long knife to slice into squares.