I use the recipe on the marshmellow fluff jar too. But, here is what we do that makes it kind of special. First, I use butter not margarine, it makes a huge difference. Second, when the fudge is done, but still hot in the pan, we take tablespoons and plop out discs of fudge. (Cover a table with foil and after you make the discs let it set up until fully set.) It makes it like little cookies. We make this a family thing a week or so before Christmas. My kids are grown and still come home for fudge day.
This year will be very sad if Tanner (grandson now in Air Force basic training) can't come. Still, everyone just loves these. They keep asking me for the recipe and I tell them it is a secret that I will pass on before I go. Hee Hee. I don't have the nerve to tell them it is the fluff recipe. I have used vanilla chips in it and if you use really good ones it is so very good. I have also used milk chocolate and butterscotch.