I used coconut oil. The gravy of this curry has a medium thick consistency, so adjust the amount of water accordingly. I think back home this is made with a type of Mango called “chandrakaran”, am not sure about it though. Usually, it's made with mangoes which are smaller in size (at least I think so ;). My amma was saying sometimes a little jaggery is added towards the end of cooking to give it more sweetness. I haven't tried it that way. Please give it a try, if you like that flavor.