Add the sugar and milk to a heavy-duty saucepan over medium heat and bring to a boil, stirring constantly.
Boil for 3 minutes all the while stirring. Remove from heat.
Stir in the peanut butter and marshmallow creme, keep stirring until smooth and well combined.
Pour over the chocolate fudge and spread evenly from edge to edge. Let cool 15 - 20 minutes then cover with foil and refrigerate overnight.
Use the foil to lift the fudge out of the pan to a cutting board.
Peel off the foil and cut into squares with a chef's knife. For clean cuts dip the knife into hot water and wipe it off between each cut.
Store fudge tightly covered in a cool dry place up to 2 weeks.