Line a 13x9 glass baking dish with parchment paper. Set aside.

In a large saucepan, heat granulated sugar, butter, salt, 1/4 cup cinnamon sugar mix, and heavy cream until combined. Bring to a rolling boil and stir continuously for 4 minutes.

Remove from heat. Quickly stir in white chocolate morsels, marshmallow cream, and 2 Tbsp cinnamon sugar. Whisk vigorously until smooth. Be patient, this may take a couple of minutes. Works best with an electric mixer.

Pour fudge into prepared pan and refrigerate for 3 hours, until hardened.

Remove from pan, remove parchment paper, and lay fudge on a cutting board. Cut into small bite-sized pieces.

To make drizzle, whisk together the powdered sugar, maple syrup, and heavy cream until smooth. Pour into a ziploc bag, and snip a tiny piece off the corner. Drizzle over cut pieces of fudge. Sprinkle immediately with remaining 1 tsp of cinnamon sugar sprinkles. Place fudge back in refrigerator until icing hardens, about 15 minutes.