best double chocolate cookies in the world

thank Donna Hay

120g dark chocolate, chopped
110g unsalted bautter, softened
3/4 cup brown sugar
1 egg
1 teaspoon vanilla extract
1 cup plain flour, sifted
1/4 cup cocoa powder, sifted
1 teaspoon bicarbonate of soda
280g dark chocolate, extra, roughly chopped

Preheat the oven to 160 degrees celsius. Place the chocolate in heat proof bowl over a saucepan of simmering water and stir until the chocolate is melted and smooth. Set aside. Place the butter and sugar in the bowl of an electric mixer and beat for 8-10 minutes or until light and creamy. Add the egg and vanilla and beat for a further 3-4 minutes. Stir through the flour, cocoa, bicarbonate of soda and melted chocolate. Add the extra chopped chocolate and stir to combine. Roll tablespoons of the mixture into rounds. Place on baking trays lined with baking paper, allowing room for the cookies to spread, and flatten slightly. Bake for 10-12 minutes or until cracks begin to form. Cool on wire racks. Makes 16.