Preheat oven to 150C. Sift flour and bake for 25mins. Stir occasionally while baking, then remove from oven and leave to cool.
Keep oven heated at 150C.
Beat butter and icing together until soft. Add ground almonds and mix well. Add flour and mix with a spatula until a smooth dough forms.
Roll dough out to a thickness of 1 cm. Cut out shapes using your preferred pastry cookies cutter and place them on a baking tray lined with parchment paper.
Bake for 20-25 minutes. Remove from heat and cool on a wire rack.
Dust cooled polvorones with icing sugar. Serve or store in an airtight container to keep them crisp.