Chocolate Brownie Cookies

In a medium bowl, mix together cocoa, caster sugar and vegetable oil. Beat in eggs one at a time, then stir in the vanilla. Combine the flour, baking powder and salt; stir into the cocoa mixture. Cover dough, and chill for at least 4 hours.

Preheat oven to 180 C / Gas mark 4. Line baking trays with parchment. Roll dough into 2.5cm balls. Coat each ball in icing sugar before placing onto prepared trays.

Bake in preheated oven for 10 to 12 minutes. Let stand on the baking tray for a minute before transferring to wire racks to cool.