loved this, i did not have the mango powder either, but added some coriander root and a 1/2 tsp of fresh unripe smashed mango (no idea if it would get close, but was looking to do what the other reviewer said it was great for...sharpness and accentuating)Either way it worked well.
Perfect combination of spices and prawns. The marinade is well balanced between hot notes (chili), tart notes (lemon) and the more comple flavours of tumeric and especially garam masala. I used our homemade garam masala and for this recipe it is essential to use the best spices. I have broiled the prawns at 530 F (275 C) for 4 minutes each side. But instead of butter I have brushed them with the marinade. To add lemon juice and mango powder before serving is fantastic, because it emphasizes the tart flavours which are needed to bring up all the different spices. As side dishes I served Paratha (whole wheat bread) and Kheera Raita (cucumbers in mint-flavoured yogurt). Thanks for sharing such a fantastic recipe.
I couldn't find mango powder anywhere, so I just added a can of mango nectar to the marinade part. Delicious. Perfect heat, wonderful shrimp flavor.