Grease a 10cm/4in chefs' ring with butter and place onto a plate.
Place the cream cheese, icing sugar, cocoa powder and cream into a bowl and whisk together.
Press the biscuit crumbs into the bottom of the ring mould, then add the cream cheese mixture to fill the ring.
Smooth over the top and sprinkle the chocolate over.
Carefully remove the ring and top with the orange segments and mint.
For the crème anglaise, heat the milk and cream in a saucepan over a medium heat, until nearly boiling, then remove from the heat.
In a bowl, beat together the egg yolks and sugar, then gradually add the warmed cream mixture, stirring constantly.
Return the mixture to the saucepan. Add the cardamom and vanilla seeds and stir over a low heat, until thickened enough to coat the back of a spoon.
Strain the mixture through a sieve into a bowl and allow to cool.
For the spun sugar, melt the sugar in a small frying pan until golden, then remove from the heat. Using a fork, flick strands of the caramel over an upside-down bowl. Allow to set, then remove and serve over the cheesecake with the crème anglaise poured around.