Pulse together the flour, cornflour, salt, icing sugar and butter in a food processor until it comes together to form a dough in the machine. Remove the dough, knead gently and form into a ball. Wrap in clingfilm and chill for 60 minutes.
Pre-heat the oven to 180° C.
Remove from the fridge and roll out on a lightly floured surface to 1cm thickness. Cut out shapes from the dough using an angel-shaped cookie cutter. Grease and line 2 baking trays. Arrange on the baking trays spaced apart then bake for 12-15 minutes until they just start to colour. Remove from the oven and sprinkle immediately with the caster sugar.
Allow them to cool on the sheets before transferring to a wire rack to cool completely.
Bore two small holes in the cookies in the centre of the wings (roughly between the wings) and thread ribbon through the holes, tying securely behind them. Serve on nonstick baking paper.