Line an 8inch square baking dish with parchment paper and set aside.
Prepare your mixing bowl by adding the marshmallow cream, white chocolate morsels and vanilla bean. Pour these ingredients (unmelted) into the mixing bowl and set aside.
In a large saucepan, melt butter with sugar, heavy cream and salt over medium high heat. Bring to boil. Stirring constantly, boil for a complete 5 minutes. Remove from heat.
Pour hot mixture over ingredients in your mixing bowl. Using an electric mixer with whisk attachment, beat on medium until smooth and creamy (about one minute). Pour into prepared baking dish.
Refrigerate hot fudge for two hours, until set (or overnight).
Remove parchment paper and cut into bite size pieces.
If desired, pour melted chocolate into a ziploc sandwich bag, snip off the corner and drizzle over tops of fudge pieces. Add sprinkles and enjoy.
Store fudge in an airtight container in the refrigerator for up to 3 weeks. ENJOY.
Notes
To scrape a vanilla bean, slice it lengthwise from end to end. Using the tip of the knife "dig" out the beans until all have been removed. Save used vanilla bean and place it in a jar of granulated sugar to make Vanilla Sugar.