Preheat the oven to 400 degrees F. Fit a small baking sheet with parchment paper or generously grease it.
Roll the puff pastry out on a lightly floured surface.
Brush the butter over it from edge to edge.
Sprinkle the cinnamon over the butter from edge to edge followed by the brown sugar.
Press it down lightly with the palm of your hands to help it adhere to the butter.
Roll it up. If you have time, refrigerate for 20 minutes.
Using a serrated knife slice into 8 equal pieces and lay it on the parchment paper - barely touching.
Bake 16 minutes.
Make the icing: whisk the sugar, milk and vanilla together - add more sugar or milk if needed to get the right consistency.
Spoon over the rolls and use the back of the spoon to spread it out.
Devour. Be happy. :)