Heat oil in a large frying pan or skillet over medium-high heat.
Add onions and 1 sprig of curry leaves. Sauté, stirring occasionally, for about 2-3 minutes or until soft and translucent.
Add tomatoes and green chilies. Sauté, stirring occasionally, for about 2-3 minutes or until the tomatoes turn mushy.
Add coconut paste. Stir to combine. Sauté, stirring constantly, for about 2 minutes or until aromatic.
Add tamarind pulp or paste and 1 cup water. Season with salt. Stir to combine.
Bring to a boil.
Add prawns and 1 sprig of curry leaves. Stir to combine.
Bring to a boil. Cook, covered, for 7-8 minutes or until prawns are cooked through.