12 mins prep. time
20-25 mins cooking time
160°C (325°F)/Gas Mark 3
What you need:
Put the plain flour and cornflour in a mixing bowl. Add the butter and rub in with your fingertips until the mixtures looks like breadcrumbs.
Stir in the sugar and chocolate. Squeeze the crumbs together in your hands to form a ball.
Press the mixture into an ungreased shallow cake tin (I used an 18cm (7 inch) tin). Prick the top with a fork. Mix the cinnamon and a little sugar together and sprinkle on top. Bake in a preheated oven, 160°C (325°F)/Gas Mark 3, for 20-25 minutes until pale golden.
Remove from the oven and leave to cool. Cut the shortbread into bars and store in an airtight tin for up to 5 days.