Preheat oven to 200°C/180°F. Grease 3 x 12-hole (2-tablespoon/40ml) deep flat-based patty pans.

Combine cinnamon and ¼ cup of the sugar in a small bowl. Sprinkle each pastry sheet well with cinnamon sugar. Roll each sheet up tightly, cut into 12 equal-sized rounds. Place rounds cut-side down. Roll each round into a circle with a diameter of 9cm (3¾-inch), using your fingers, press rounds into pan holes ensuring pastry is pressed firmly into the base of the pan. Freeze for 5 minutes.

Whisk remaining sugar, egg yolks, cornflour and custard powder in a medium bowl until just combined. Combine milk and vanilla in a medium saucepan, bring mixture almost to the boil. Whisking continuously, gradually pour milk mixture into egg mixture, return custard mixture to same saucepan. Cook custard over low heat, stirring continuously, until mixture boils and thickens, remove from heat. Transfer mixture to a large jug.

Pour custard mixture equally between cases (about 1 tablespoon each), bake 15 minutes or until pastry is golden and custard just set, cool.

Just before serving, dust cooled tarts with sifted icing sugar. Using a kitchen blowtorch, caramelise the tops of the tarts.