I have been making this recipe for a number of years. It is truly high fat and high calorie.
The Easiest Best Fudge Ever:
1 cup sugar
1/2 tsp salt
3 Tbl unsalted butter
1/2 cup heavy cream (ie. whipping cream)
1 3/4 cup miniature marshmallows
1 1/2 cups of chips (use any flavor! Chocolate, peanut butter, vanilla, butterscotch, mint, etc)
1/2 tsp vanilla or whatever flavor extract you would like (almond, peppermint, etc.)
Combine sugar, salt, butter, cream and marshmallows in a heavy medium saucepan. Set over medium heat, cook, stirring until butter and marshmallows are almost melted. That will take about 5-6 minutes. Bring to a boil, stirring occasionally for 5 minutes. Take off burner. Add chips and flavoring to pan. Start stirring and keep that going until all the chips are melted and it looks all nicely mixed. Pour into a 8x8 pan lined with parchment paper. Let sit for 3 hours (or 1 in the fridge) before you take out of the pan.
Store wrapped tightly, and yes, this one needs to be kept reasonably cold due to the dairy.