Heat oil in a pan, and add fennel seeds. Once they splutter, add the chopped onions and sauté until golden brown.
Add the ginger-garlic paste and green chilies. Sauté until fragrant.
Add chopped tomatoes, turmeric powder, red chili powder, coriander powder, cumin powder, and a pinch of salt. Cook until the tomatoes soften and the oil starts to separate.
Add the grated coconut and poppy seeds. Stir well and cook for another 2-3 minutes.
Add prawns to the pan and mix well, allowing them to coat with the masala. Cook for 5-7 minutes, or until prawns are cooked through.
Add tamarind paste or pulp and a little water (if needed) to achieve the desired consistency. Stir everything together.
Let the curry simmer for another 5 minutes to allow the flavors to meld.
Garnish with curry leaves and fresh coriander leaves.
Serve hot with rice or Indian bread (roti, naan). Enjoy your Chettinad Prawn Masala!