Marinate the prawns with a pinch of salt, turmeric powder and red chili powder for 10-15 minutes.
Make a paste of all the dry powdered spices (garam masala powder, turmeric powder, coriander powder, cumin powder and red chili powder) except salt with some water to form a paste. Keep aside.
Heat 1 tbsp. oil in a pan and fry the prawns for 2-3 minutes. Drain and keep aside. Heat the remaining oil and temper with whole spices - mustard seeds, fennel seeds, fenugreek seeds, cinnamon, cardamoms, cloves, asafoetida and star anise. Saute for a few seconds.
Now add the onion, ginger, garlic, green chilies and curry leaves. Fry till light brown. Add the tomatoes and saute till it is mashed.
Add the spice paste and fry till the oil separates. Add the fried prawns and salt to taste. Mix everything well and add 1/2 cup water.
