1. Line an 8-inch square pan with parchment paper, leaving enough overhang to lift the fudge out easily after chilling.

2. In a saucepan over low heat, combine the white chocolate chips, cream cheese, sweetened condensed milk, and butter. Stir until fully melted and smooth.

3. Add the vanilla extract and salt, then stir until the mixture is glossy and evenly combined.

4. In a small bowl, mix the brown sugar and ground cinnamon together.

5. Spread half of the fudge mixture into the prepared pan. Sprinkle half of the cinnamon-sugar mixture over the top.

6. Add the remaining fudge mixture and smooth it gently. Sprinkle the rest of the cinnamon-sugar mixture over the top.

7. Use a butter knife or skewer to lightly swirl the cinnamon mixture through the fudge without overmixing.

8. Refrigerate for 3 hours, or until fully firm.

9. In a small bowl, whisk together the powdered sugar and milk until smooth.

10. Drizzle the icing over the chilled fudge and dust lightly with extra cinnamon if desired.

11. Lift the fudge from the pan, slice into squares, and serve chilled or slightly softened at room temperature.