Clean and marinate prawns with turmeric and salt for 10 minutes.
Heat mustard oil or ghee in a pan and lightly fry the prawns for 1–2 minutes. Remove and set aside.
In the same pan, add onion paste and sauté until golden.
Add ginger-garlic paste and cook until the raw aroma disappears.
Add turmeric powder and mix well.
Pour in coconut milk and stir gently to form a smooth gravy.
Add a little water if you prefer a soup-like consistency.
Return the prawns to the pan and simmer for 5–7 minutes.
Sprinkle garam masala and adjust salt.
Serve hot as a rich soup or with steamed rice.