Clean and devein the shrimp. Skin and slice the mangoes thin. Slice the shallots, ginger and garlic into thin strips. Slit the chilies for spicy curry or leave it whole. Grind the coconut into a smooth paste with a few table spoons of water.
Cook the curry
If the mango is tart add ½ C to a pot along with ½ C sliced shallots , ginger, garlic chilies, turmeric powder and chili powder. Add 1 C water and bring it to a rolling boil. Simmer for 5 minutes. Add salt and taste , if needed add more mango slices to make it more tart.
Increase the heat and add the shrimp. Stir and cook for 2 to 5 minutes until the shrimp turns opaque. Reduce the heat and add the ground coconut paste (or thick coconut milk or canned coconut milk). Stir well , taste and adjust salt if needed. Turn off the heat as soon as it begins to simmer. Add a few tablespoons of hot water if you want to thin the curry.
Season
In a small sauce pan heat 1 tbsp of oil. When hot add all the ingredients for tempering. Once the mustard splutters turn off the heat. Pour the hot oil and the seasoning over the curry. Stir just before serving
Notes
Use as many or as few green chilies as you prefer.
Leave the chilies whole for a less spicy curry , slit them to make it spicier.
Store bought fresh/frozen shrimp might have added sodium. It is always better to start with less salt and adjust later.
Coconut milk can be substituted for ground coconut. Use roughly the same amount. Adjust to taste.
If using fresh coconut milk - cook the mangoes in thin milk instead of water and finish the curry using thick coconut milk in the end.