100 grams icing sugar
200 grams plain flour
100 grams cornflour or rice flour
200 grams very soft unsalted butter
1 tsp Vanilla Extract or Vanilla Paste
Preheat the oven to 160° C/140° C Fan/gas mark 3/325°F.
Put the icing sugar, plain flour and cornflour into the bowl of a food processor fitted with the double-bladed knife and give them a quick blitz. (This will save you sieving). If you don’t have a food processor, simply sieve the icing sugar, plain flour and cornflour into a large bowl.
Combine softened butter with the extract or paste and add to processor or combine using a hand whisk.
Process again until the soft mixture coheres and begins to form a ball, loosely clumping around the blade/whisk.
Turn this out onto a clean surface and form into a sausage shape, place onto a piece of cling film long enough to accommodate the sausage of dough and roll up tightly, leaving enough cling film at each end to be able to get hold of.
Holding each end of the cling film, pick up the dough and spin the dough to form an even round shape and put in the fridge to firm up (1hr).
When dough is firm, cut approx. 7mm thick biscuit pieces cutting through the cling film and removing clingfilm from the edge after cutting, before placing on to a baking tray lined with parchment.
Put tray in oven and bake for about 20-25 minutes, by which time the shortbread will be pale still, but not doughy.
Remove the tin from the oven and leave to cool for 10 minutes or so, before removing with a palette knife to a wire rack. Sprinkle with the caster sugar and leave them to cool completely before eating or storing in a tin.