Get ready with all the ingredients. Clean and wash crab thrice and cut as per your requirement.
In a wide pan add oil on a medium heat and add chopped onion and saute until it is translucent.
Add chopped tomatoes ,green chilles (slit into half )and saute for a minute.
Add ginger garlic paste and salt to taste and stir until raw smell disappear .
Cover with a lid and cook until it turns mushy.
Meanwhile, in a kadhai or pan dry roast fennel seeds, cumin and rice together for a minute or until it starts to splatter. Remove from heat and cool aside.
Grind roasted ingredients in a mixer grinder into fine powder and keep it aside.
When the onion tomato mixture turns mushy add masala powder and mix well.
Add cleaned crab to the masala mixture and add turmic powder and gently stir or toss according to your convenience.
When the masala is well coated on to the crab add 1 cup water and cook until crab colour changes to orangish red.
Grind coconut to fine paste and add to the crab curry along with the rice fennel and cumin roasted powder.
Stir gently and further cook until gravy starts to thicken and oil starts to float on the surface . Finally add in curry leaves and remove from stove top.
Before serving garnish with coriander leaves .Delectable mildly spicy Crab curry/Nandu masala is all set to devour as it is or can serve with rice and rotis. It is best to serve as a side for south indian sambhar rice and Rasam rice .