Heat oven to 190°C (375°F). Whizz butter with both sugars in food processor. Add beaten eggs, sifted flour, baking powder and salt and whizz again. Chop dark chocolate (if using) into little chunks. Stir chocolate and nuts and vanilla into mixture. Plop spoonfuls of mixture onto a nonstick baking tray, allowing room to grow.
Bake for 10 to 15 minutes until lightly golden. Cool on a wire rack and store in an airtight container.
© 1998 All rights reserved. Published by Murdoch Books.