Line a 8×8 inch baking pan with parchment paper leaving some hanging over the side for easy removal.
Add the Hot Chocolate Mix, Heavy Cream, and Butter to a medium pot over medium low. Stir together until the butter has melted, the powder has dissolved and the mixture is blended well. 1/4 cup Hot Chocolate Mix, 2 TBS Heavy Cream, 2 TBS Unsalted Butter
After it is dissolved (check with your fingers to make sure its not grainy) add the Sweetened Condensed Milk and stir until totally mixed and creamy. 14 oz Sweetened Condensed Milk
Remove from the heat and add in 3 cups of the chocolate chips. Stir until they are totally melted. (Add back to the heat over low if they won't melt all the way without.) Stir in the Vanilla Extract. 3 1/2 cups Chocolate Chips, 1 tsp Vanilla Extract
Pour the fudge into the prepared pan. Spread it evenly to the edges and corners of the pan.
Sprinkle the mini marshmallows over the top of the fudge, and press them into the fudge lightly so they stick better. 1 cup Mini Marshmallows
Add the remaining 1/2 cup of chocolate chips to a small microwave safe bowl and microwave in 30 second increments until you can stir it smooth. Drizzle the chocolate over the top of the mini marshmallows.
Cover the pan and let the fudge sit until it is set, a few hours. Or place it in the fridge to chill for a couple hours. Once set, lift the fudge out of the pan and cut it into small pieces with a sharp knife, and enjoy!