Add the Rum, cranberries, star anise, cardamom, cinnamon stick, and bay leaf in a pan.
Bring to a boil and continue to cook on medium-low heat for 10 minutes. Cover and let it cool down for about 20 minutes. This will also intensify the flavours and would allow the cranberries to soak in the flavours of the rum.
Till the rum mix cools down, get started on your chocolate ganache. Break the chocolate into small pieces and melt it on a double boiler.
In a pre-chilled bowl, add the cream and the melted chocolate and whisk well. Chill for 10 minutes in the freezer.
Remove the whole spices from the rum mix and add it to the chocolate ganache, whisk well. Chill again for 10 minutes.
Take out the tart from the freezer and add the ganache mix. Spread evenly and chill for about an hour.
Remove from the outer shell, garnish with more cranberries and biscuit crumble, chocolate shard, mint leaves, and serve.