10cardamom podsseeds removed and ground into a fine powder
Preheat the oven to 150/300/gas2. Grease an 8" quiche dish.
Dust off your mixer and cream the butter and sugar together until it is light and fluffy.
Sift in the flour, cornflour and cardamom powder and mix gently with a spoon until it is beginning to combine. Next get your hands on there and smush the crumbs up into a dough. You'll think this recipe is rubbish and it'll never form a dough, just hang on in there and keep going ;)
Turn out onto a lightly floured surface and roll out gently until it is around the size of a dinner plate.
Carefully pick up the slab and lay it into the quiche dish, don't worry if it breaks up or otherwise misbehaves, just squidge it into place with your fingers and smooth over with a large spoon until it is relatively flat. Score out 'petticoat tails' into the dough for as many pieces as you want (I scored into 8) and use a fork to gently prick the shortbread all over.
Bake in the preheated oven for 50 minutes, sprinkle with a little more sugar when it first comes out and let cool slightly before removing from the tin and letting cool fully on a cooling rack.