Wash and clean the prawns.

Marinate the prawns with 1 teaspoon turmeric powder, 1 teaspoon red chilli powder, 1 teaspoon salt, and juice of half a lemon for 30 minutes.

Take 1 cup of grated coconut, pour over 1 cup of boiling water, and extract the coconut milk through a sieve.

Grind the following ingredients with some water to make a paste: 3 pearl onions, 2 green chillies, 2 teaspoons chopped garlic, 1 teaspoon chopped ginger, 1/2 teaspoon cumin powder, 1 teaspoon coriander powder, 1/2 teaspoon turmeric powder, 1 teaspoon tamarind paste.

In a heavy-bottomed pan, fry the prawns on both sides in mustard oil for 3 to 4 minutes. Remove and set aside.

In the same pan, add a little more oil, and when hot, add mustard and fenugreek seeds.

Once they start to splutter, add curry leaves, dry red chillies, and onions.

Fry until the onions turn light brown, then add the ground masala paste.

Sauté for 5 to 6 minutes, or until oil separates from the masala, on medium heat.

Add salt and tamarind paste, and cook for another 3 to 4 minutes.

Add the prawns and cook for 3 to 4 minutes.

Pour in the coconut milk, bring to a boil, then lower the heat and simmer the curry for 2 to 3 minutes.

Turn off the heat, cover the pan to trap the aroma.

Serve hot with steamed rice and raita.