In a large bowl cream together the butter and rapadura until smooth. Beat in eggs one at a time then stir in vanilla.
Combine the flour, bicarbonate of soda and salt. Now stir into the creamed mixture until just blended. then mix in the oats, walnuts and chocolate chips.
Drop heaped spoonfuls on an ungreased baking tray. Flatten to 15mm thick for a thinner biscuit.
Bake for 12 minutes in the preheated oven. Cool the biscuits on baking tray for 5 minutes then finish cooling on a cake rack to cool completely.