Preheat oven to 200°CTake a sheet of puff pastry and place it on a silicone baking mat. Combine the brown sugar and cinnamon in a bowl.Brush the inside of the puff pastry with the melted butter then sprinkle the brown sugar and cinnamon evenly over the surface.Begin to roll the sheet down to the bottom edge as tight as you can, like a swiss roll.Use a sharp knife, cut the roll into 1-inch slices, and place in a lightly greased baking pan, and bake for 20 - 25 minutes or until puffed and browned.For the icing: Whisk the icing sugar, milk, and vanilla together until runny yet slightly thick. Drizzle over warm rolls and Enjoy!