Peel and roughly chop your mango. Peel your bananas.Add all these lovely things and your coconut milk to a blender. Whiz till smooth. Blend in 1 tsp turmeric and 250ml water, then serve over ice.
You can ripen your mango but popping it in a paper bag with the bananas. Leave them on a windowsill for 2-3 days and they'll all be ready to blend.