Thaw the puff pastry sheet as per packaging instructions.
In a bowl, add melted butter, cinnamon powder, dark brown sugar and mix everything well without any lumps. Keep aside.
Carefully unfold the pastry sheet onto a clean surface.
Spread the butter, cinnamon mixture evenly on to the pastry sheet leaving 1 cm from the edges.
Sprinkle brown sugar on the sheet and roll up carefully. Keep the rolled sheet in the fridge for 10 minutes.
In another small bowl, mix powdered sugar along with milk and vanilla extract for glazing. Keep aside.
In meanwhile preheat the oven to 180 °C
Grease and line the baking tray with parchment paper.
Once 10 minutes is done, cut the pasty roll into even pieces and place it on the baking tray.
Bake for 20-22 minutes or until they turn into golden colour. (mine done at 20 minutes)
After taking it from the oven allow it to cool in the tray for 5 minutes. Then drizzle the icing on the rolls and enjoy delicious and flaky cinnamon rolls warm or cold.