For the prawns:
Clean the prawns apart from the heads.
Adjust the temperature of the Big Green Egg to 190 degrees.
Place all the other ingredients apart from the fennel in a bowl. Add the prawns and cover with a plastic membrane. Leave in the fridge for 2-4 hours.
For the sauce:
Place all the ingredients in a blender and blend well until a smooth mixture is formed.
When the sauce is ready, heat it for 3-5 minutes on the Big Green Egg and season the flavour if needed.
Remove the prawns from the marinade and cook them on the Big Green Egg. Close the lid and allow to cook for 7-8 minutes.
Finally, serve with the fennel and the mango sauce.