There is an extremely thin layer on brain which should be removed very tactfully holding the brain in your palm.
Clean and wash brain thorougly in such a way that each piece remain intact and does not break into pieces.
Boil brain in 2 cups water adding turmeric powder.Cook till water dries up completely.
Heat oil in a separate pan and add onion. Fry onion till light brown. Add ginger garlic paste.Stir for 20 seconds. Add chilli powder,salt and tomatoes. Stir for 1 min. Add brain and stir lightly, gently breaking each brain into 3-4 pieces. Add fenugreek leaves.
Cover the pan with a lid and let it simmer for 5-7 minutes on a low heat till tomatoes are completely pulpy.
Stir for 1 more min. till oil separates
Pour the content in a dish and decorate with corriander leaves.