Place biscuits and butter in TM bowl, mill for 10 seconds, speed 7. Use hands to press firmly into the bottom of a 23cm lined springform pan (I only line the base of the tin and not the sides; read the note below!). Place in refrigerator.
Place 300g milk and gelatine in a cup or bowl and stir to combine. Set aside.
Add remaining 500g milk, sugar, cocoa and chocolate, cook for 5 minutes, 70°C, speed 2.
Add gelatine mixture, mix for 30 seconds, 70°C, speed 3.
Add cream, mix for 10 seconds, speed 3. Pour chocolate mixture over biscuit base. Refrigerate for a minimum of 4 hours, or until set. Serve straight from the fridge.
