Lightly grease a 6" ground cake ring with butter. Place on a parchment lined sheet pan and set aside.

Cream and the softened butter and sugar together in a stand mixer fitted with paddle attachment until the mixture is a light yellow color. Meanwhile, melted the 4oz of chocolate over a double boiler over medium low heat. Add the butter and sugar to the chocolate, stirring constantly. Add the egg and continue stirring.

Fold in the biscuit pieces with the chocolate mixture until mix thoroughly.

Pour the biscuit mixture into the prepared ring mold and gently flatten and press into the edges. Refrigerate for 3 hours.

Remove the cake from the refrigerator. Remove the ring mold and place bottom side up it on a cooling rack. Set aside. Meanwhile, melt the 8oz of chocolate over a double boiler. Once smooth, pour it over the cake and smooth it with a spoon or offset spatula. Let the chocolate harden in room temperature.

Transfer the cake to a plate. Melt the white chocolate and drizzle on top.