Mix all the ingredients in a blender until they come together. Scoop out the dough and press into a 20cm (8in) fluted tart tin. Chill for 2 hours to firm. Towards the end of the 2 hour period, preheat the oven to Gas Mark 3, 170°C, fan 150°C.
Put in the oven and bake for 15 minutes. Remove and lightly prick all over with a skewer. Cut into 8 triangles and sprinkle with more sugar. Return to the oven for 10-15 minutes until golden and sandy to the touch. Allow to cool in the tin.
See more British classics recipes
Freezing and defrosting guidelines
This recipe can be frozen, after chilling it in the refrigerator for 2 hours (before the baking stage), and kept in the freezer for up to three months. Always defrost and heat thoroughly before eating.