Prep a baking sheet with parchment paper and set aside.
In a small microwave safe bowl, heat butter until barely melted. Add brown sugar and cinnamon, and stir to combine. Set aside.
In a double boiler, melt white chocolate over low heat, stirring constantly until completely melted.
Pour white chocolate onto prepped baking sheet and spread into an even layer.
Drop a tablespoon of sugar mixture into several different places across the top of the bark, then drag a knife across across the length of the pan through each spot of dropped sugar, back and forth to create the swirls you see in the pictures above.Alternatively, you can drizzle the sugar mixture in a few evenly spaces parallel lines that run the width of the pan and then drag a knife through them perpendicularly to create the same effect.
Place the pan in the freezer for at least an hour to let it set, then cut it using a large knife or rocking pizza cutter to create individual pieces.
Keep stored in an airtight container until ready to eat - they will get slightly soft when left at room temperature. Enjoy!