To bake as cookies: heat the oven to 180C/fan 160C/gas 4. Line a large baking tray with parchment. Divide the dough into 12 balls (about the size of walnuts in their shell). Flatten the balls into discs and arrange on the tray. Bake for 10 minutes until turning golden around the edges. Cool on the tray for 5 minutes, then lift onto a wire rack to cool completely.
To make cookie dough bars: line a 900g tin with baking parchment. Press the dough into the base of the tin, flattening the top with the back of a spoon. Chill for 4 hours, then turn out onto a board and cut into 10 bars. Wrap each in baking parchment.