Fry the fish pieces until crisp and brown. Break into smaller pieces and keep aside.

Grind one pod of garlic, ginger, cumin seeds, black peppercorns, red chilli powder, and 3 tbsp vinegar into a smooth paste.

Heat the oil in a wok (kadhai). Remove from heat, cool and add turmeric powder. Return to heat, add the ground paste and fry till it browns. Add fish, green chillies, mustard seeds, and the remaining pod of garlic (slit). Cook for 5 minutes.

Remove from heat and add the remaining vinegar and salt. After it cools store in airtight jars. Make sure the pickle is covered with oil. If not, then heat some oil, cool and then add to the pickle.