Fantasy Fudge

This recipe has been around for years, and I've been making it for years.  It is pretty much no-fail and is creamy and delicious.  I only make it at Christmas time and I don't make it every year.  But I did this year to serve at a party, so I thought I would share the recipe:
Fantasy Fudge
1 1/2 cups butter
6 cups sugar
2 cans evaporated milk (you can substitute 1 of the cans of milk with 1 1/2 cups of cream.  It makes the fudge more, well, creamy)
4 cups semi-sweet chocolate chips
1 large (13 oz.) jar of marshmallow crème
1 Tablespoon vanilla
2 cups chopped nuts, optional

Lightly butter a 13 x 9 pan.  Mix sugar, butter, and milk in a large, heavy pan.  Bring to a full, rolling boil on medium high heat, stirring constantly.  Continue boiling until to softball stage.  Remove from heat and stir in chocolate chips, marshmallow crème and vanilla.  Pour into prepared pan and cool.  Cut into squares when completely cool. You can wrap the squares in plastic wrap or serve them in candy paper liners.