In a large mixing bowl, add marshmallows, chocolate morsels, unsweetened chocolate, and vanilla extract. Set aside.
In a large saucepan, combine sugar, milk and butter. Over medium high heat, bring mixture to a boil while stirring constantly. Once boiling, boil for a full two minutes.
Pour hot mixture over marshmallow and chocolate and beat with whisk attachment until melted and smooth (may take several minutes).
Pour into prepared baking sheet and refrigerate for about 3 hours (or overnight). Remove from refrigerator and cut into 4 large rectangles. Wrap in parchment paper and store in airtight container until ready to use.
When ready to use, cut into bite sized pieces and enjoy.
Video
Notes
Put the chocolate, marshmallows and vanilla in a mixing bowl first. Then, when the butter mixture is done boiling you can pour it directly into the mixing bowl.
I pour the Fannie May Fudge into a large 15 x 10 x 1-inch baking sheet that’s lined with parchment paper. Once it’s chilled and firm, I will remove it from the pan and cut it into approximately 4 large rectangles.
I store these rectangles wrapped in parchment paper and in an airtight ziploc bag in my freezer. I usually make this fudge mid-December and store it in my refrigerator in these “packs.”