Preheat the oven to 200°C, fan 180°C, gas mark 6. Place the cranberries, caster sugar, port and ground cinnamon in a small saucepan.
Cook over a medium heat for 10-15 minutes, stirring occasionally until the cranberries have popped and some of their juices have been released.
Roll out the pastry and use a medium round pastry cutter to cut out 12 discs, then cut 12 small star shapes from the trimmings.
Gently press the pastry discs into the holes of a 12 hole tartlet tin (or mini muffin tin), and fill each with 1 teaspoon of the cranberry sauce.
Brush the under side of the stars with water and place on top of the cranberry filling.
Bake for 15 minutes or until the pastry is golden brown. Dust with icing sugar to serve.
Cook's tip: Don't panic if you haven't got a mini muffin tin, you can buy one from our Sainsbury's baking range.