Beverly Hills cookie recipe

Name: Cookie recipe
Prep time: 15 mins
Cook time: 8-9 mins
Yield: 18 cookies
Ingredients: 120g (½ cup) butter; 110g (½ cup) soft light brown sugar, firmly packed; 100g (½ cup) granulated white sugar; 1 egg; ½ tsp pure vanilla extract; 140g (1 cup) plain (all-purpose) flour, plus extra for flattening the cookies; 110g (1½ cups) oatmeal, whizzed to a fine powder (1¼ cups after blending) in blender or food processor.; ½tsp baking powder; ½tsp bicarbonate of soda; ¼tsp salt; 170g (1 cup) plain (semi-sweet) chocolate chips; 85g (3oz) plain (semi-sweet) chocolate, grated; 75g (¾ cup) walnuts, toasted then chopped, optional