Preheat the oven to 325F. In a small sauce pan, heat milk, cream, star anise, and cardamom along with the mango puree on low heat until hot, but not boiling.
Allow to simmer for a few minutes, and take off the stove to allow the spices to infuse into the cream. Meanwhile blend the eggs in a blender with the sugar and salt, until well blended. Now at this time remove the star anise. Pour about half of the cream mixture and mix. Add in the rum at this moment. Stir into the rest of the cream mixture. Mix everything well.
Pour this mixture into 2 ramekins or if a little extra then 3 ramekins. Place the ramekins in a deep baking dish and pour hot water half way up the sides of ramekins. Cover it with a foil and place the dish into oven.
Cook for 30 to 35 minutes until the it looks set. Remove and check, jiggle a little bit so you can see whether it is ready or not. Then, cover them plastic wrap and refrigerate it till cool for about 3 hours or so.
When you are ready to serve , simply add a dollop of freshly whipped cream and mango slice.