Crunchy, crumbly shortbread with bursts of sweet cranberries.
In a large bowl, cream together the sugar, butter and vanilla extract.
Add all of the flour and cornflour. Mix it in until it starts to stick together then use your hands to press it into a ball of dough.
Add the cranberries and press them into the dough with your hands.
Refrigerate the dough for 30 minutes. Meanwhile, preheat your oven to 180°C/350°F (or 160°C/325°F for fan or convection ovens), and line a large tray with baking paper.
Once the dough is finished chilling, roll it out on a floured surface until ½-inch thick. Use a 3-inch round cookie cutter to cut out circles, rerolling leftover pieces as needed.
Bake for ~20 minutes. The edges should be firm and very slightly golden brown. The centre will be soft at first but will firm up as the shortbread cools.
Sprinkle some extra sugar on top of the shortbread while they're still warm. Then transfer them to a wire rack and let them cool completely.