1
Preheat the oven to 180°C. Spray the cake tin with non-stick spray.
2
In a large bowl, using a hand mixer or a stand mixer fitted with the paddle attachment, beat the butter for 1 minute on medium speed until completely smooth and creamy. Add the brown sugar and beat on medium speed until creamy, about 1 minute. Beat in the egg, egg yolk and BAM vanilla paste on medium to high speed until the ingredients are combined. Scrape down the sides and bottom of the pan as needed.
3
In a separate bowl, mix together the flour, cornstarch, baking soda and salt. On low speed, slowly stir in the wet ingredients until just combined. The biscuit dough will be quite thick. Add the BAM dark chocolate and stir for about 5 seconds to distribute evenly.
4
Press the biscuit dough evenly into the prepared baking tray. Bake for 20-25 minutes or until the cake is lightly golden brown. You may want to cover the cake loosely with aluminium foil after 15 minutes to prevent heavy browning around the edges. Remove from the oven and place the cake tin on a wire rack to cool completely. Once the cake is cooled, use a sharp knife or metal spatula to remove the sides of the cookie cake from the baking tray and transfer to a serving dish.