In a pan, heat 5 tbsp of coconut oil.
Add 1/2 tsp mustard seeds, fennel seeds, and fenugreek seeds.
Now, add 2 cups of sliced onions and cook until it turns brown.
Add chopped tomatoes, green chilies, 1 tsp ginger, garlic, and 15 to 20 curry leaves.
Add spices, 1 cup of water, 1 tbsp tamarind paste, and 1 tsp salt.
Cook for 3-4 minutes. You can also add 1 cup of coconut milk (optional).
Now, add 1/2 cup of water, and 300 g of cleaned prawns. Cook for 5-6 minutes.
For tadka, fry 1/4 cup of sliced onions and 10-12 curry leaves in 1 tbsp coconut oil.
Add red chili powder and saute everything.
Pour the tadka over the curry and serve!