Preheat your oven to 180°C (160°C Fan, gas mark 4) and line a baking tray with parchment paper.
In a mixing bowl, mix butter, light brown sugar and cinnamon together with a spoon until combined.
Unroll the ready-made puff pastry and spread the cinnamon, butter and light brown sugar mixture evenly over all the pastry. Leave a small 1cm gap around the surface. Then, roll the pastry like a Swiss roll.
With a sharp knife or a piece of string, cut the pastry approximately 2cm wide.
Place them on the baking tray and bake in the oven for 20 minutes. Leave space in-between each cinnamon swirl as they do expand in the oven whilst baking.
Once baked, it’s time to make the icing! In a small bowl, mix the icing sugar and water together until well combined.Using a spoon or a piping bag, drizzle the icing over each homemade cinnamon swirl in a diagonal motion from top to bottom.
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Notes
To freeze before baking: after you have rolled your puff pastry with the cinnamon filling inside. Freeze the pastry as either a log or cut it into 2cm sections. Then place it in a freezer bag or container and freeze for up to 3 months.When you're ready to eat it, continue with the recipe and bake it in the oven for 20 minutes or until fully baked and golden brown.To freeze cinnamon swirls after baking: once baked, allow the cinnamon swirls to cool down completely. Take the baking tray with the cinnamon swirls and place it in the freezer until frozen.Once frozen, place in individual freezer bags or in one freezer bag for up to a month. When you're ready to eat it, reheat in the oven at 180°C (160°C Fan, gas mark 4) until warmed thoroughly throughout.To make cinnamon swirls in advance: You can make cinnamon swirls ahead of time! Follow the recipe and store it in an airtight container at room temperature for up to 3 days. Eat them as they are, or you can reheat in the oven to gently warm them up.