Step 1

Line an 8x8-inch baking dish with parchment paper.

Step 2

In a small bowl, make the topping by mixing together the sugar and cinnamon. Set aside.

Step 3

In a large, heavy saucepan, heat the sugar, butter, and evaporated milk over medium heat.

Step 4

Bring the mixture to a boil. Leave on heat until the mixture reads 234°F-238°F on a candy thermometer (about 5 minutes).

Step 5

Once the temperature reaches 234°F, remove from heat and stir in the white chocolate chips until mostly combined.

Step 6

Beat in marshmallow fluff, vanilla, and cinnamon.

Step 7

Transfer fudge to the prepared pan. Top with the cinnamon and sugar mixture, pressing it lightly into the surface. Let fudge cool at least 2 hours before cutting and serving.