Add the sugar, salt, butter, cream, and marshmallows to a large saucepan.

Cook the mixture over medium heat until the marshmallows and butter begin to melt, about 5 minutes.

Once the marshmallows have melted, bring the mixture to a boil, and boil for 5 minutes. It will begin to brown and will bubble all over the place. Take the pan off of the heat.

Add the chocolate chips and vanilla.

Mix it all together until the chocolate has melted and everything is nice and smooth.

I add a sprinkle to just about anything, so I added some festive sprinkles to one side, and some crushed candy cane to the other. Let this sit at room temperature for 3 hours before you slice.

Cut into squares, I got about 48 squares out of my 9×13 pan. This fudge will keep at room temperature for 10 days in an airtight container.