Be sure to use a dry spoon when serving Beena Lalaji's pickle as dampness can spoil it.
To make the marinade: Place the fish pieces into a bowl, then add the chile powder, turmeric, and salt and stir well to coat the fish evenly. Set the fish aside to marinate for 1 hour.
In a deep, heavy-based saucepan, pour enough vegetable oil to fill the pan about a third of the way. Heat over medium heat until a deep-frying thermometer inserted in the oil reaches 360 degrees F or until a bread crumb sizzles, and turns golden brown when dropped in it.
Caution: hot oil can be dangerous. Do not leave unattended.
Carefully lower the marinated fish pieces into the hot oil and fry for 3 to 5 minutes, or until crisp and golden brown. Remove the fish from the oil with a slotted spoon, and set aside to drain on a tray lined with paper towels.
To make the pickle base: Heat the oil in a separate frying pan. When the oil is hot, add the mustard seeds and cover the pan with a lid. Fry for 20 to 30 seconds, or until the mustard seeds start to pop. Be careful of the popping seeds and the splattering oil. When the mustard seeds have finished popping, add the curry leaves, ginger and garlic, and fry over a low heat for 3 to 4 minutes, or until golden brown.
To make the fish pickle powder: Mix the chile powder, turmeric, fenugreek, asafoetida, and salt to a paste in a small bowl with 1 tablespoon water. Add the fish pickle powder to the pickle base mixture and stir until well combined. Continue to fry for 2 to 3 minutes or until the mixture starts to darken in color.
Place the fried fish pieces into the pan with the fish pickle paste, and stir well. Add the vinegar and bring the mixture to a boil. Remove the pan from the heat as soon as the vinegar has boiled. Season the mixture, to taste, with salt, and freshly ground black pepper, then set aside to cool.
Once the pickle has cooled, transfer it to a vacuum-sealed glass jar*. Chill the pickle in the fridge for 2 weeks before using.
*Can be found at specialty Asian or Indian markets.
Properly-handled sterilized equipment will keep canned foods in good condition for years. Sterilizing jars is the first step of preserving foods. Tips: Jars should be made from glass and free of any chips or cracks. Preserving or canning jars are topped with a glass, plastic, or metal lid, which has a rubber seal. Two piece lids are best for canning, as they vacuum seal when processed. To sterilize jars, before filling with jams, pickles, or preserves, wash jars and lids with hot, soapy water. Rinse well and arrange jars and lids open sides up, without touching, on a tray. Boil the jars and lids in a large saucepan, covered with water, for 15 minutes. Use tongs when handling the hot sterilized jars, to move them from boiling water. Be sure the tongs are sterilized too, by dipping the ends in boiling water for a few minutes. As a rule, hot preserves go into hot jars and cold preserves go into cold jars. All items used in the process of making jams, jellies, and preserves must be clean. This includes any towels used, and especially your hands. After the jars are sterilized, you can preserve the food. It is important to follow any canning and processing instructions included in the recipe and refer to USDA guidelines about the sterilization of canned products.