Prepare the Pan:
Line a 13×9-inch glass baking dish with parchment paper. Set aside.
Make the Fudge:
In a large saucepan, combine the granulated sugar, butter, salt, 1/4 cup of the cinnamon sugar mix, and heavy cream.
Heat the mixture over medium heat, stirring continuously, until it reaches a rolling boil. Boil for 4 minutes, stirring constantly.
Remove the saucepan from heat and quickly stir in the white chocolate morsels, marshmallow cream, and the remaining 2 tablespoons of cinnamon sugar.
Whisk vigorously until the mixture is smooth and fully combined. (Using an electric mixer can make this process easier.)
Chill the Fudge:
Pour the fudge mixture into the prepared pan and spread evenly.
Refrigerate for at least 3 hours, or until the fudge is firm and set.
Cut the Fudge:
Once the fudge is set, remove it from the pan and peel off the parchment paper.
Place the fudge on a cutting board and use a 1 1/2-inch circle cookie cutter to cut into circular shapes, or cut into small bite-sized squares.
Make the Drizzle:
In a small bowl, whisk together the powdered sugar, maple syrup, and heavy cream until smooth.
Transfer the mixture into a small ziplock bag and snip a tiny corner off the bag.
Drizzle the icing over the fudge pieces, and immediately sprinkle with the remaining 1 teaspoon of cinnamon sugar mix.
Set the Drizzle:
Place the fudge back in the refrigerator for about 15 minutes, or until the icing hardens.
Serve and enjoy!