Follow these step-by-step instructions to prepare your own amla pickle:

1. Prepare the Amla: Wash the amla thoroughly under running water. Pat them dry with a clean kitchen towel.
2. Cut the Amla: Cut each amla into small wedges. Remove and discard the seeds.
3. Dry the Amla: Spread the cut amla pieces on a clean cloth or tray. Allow them to air dry for a couple of hours to remove any excess moisture.
4. Roast the Spices: In a pan, dry roast the fennel seeds, fenugreek seeds, cumin seeds, mustard seeds, and nigella seeds over low heat until they release their aroma. Be careful not to burn them.
5. Grind the Spices: Once cooled, grind the roasted spices into a coarse powder using a spice grinder or mortar and pestle.
6. Heat the Oil: In a large pan, heat the mustard oil until it reaches its smoking point. Turn off the heat and let it cool slightly.
7. Add Asafoetida: Add asafoetida to the warm oil, stirring well.
8. Mix the Spices: Add the ground spice mixture, turmeric powder, and red chili powder to the oil. Mix thoroughly.
9. Combine Amla and Spices: Add the dried amla pieces to the spiced oil mixture. Stir well to ensure the amla is fully coated with the spices.
10. Add Salt and Vinegar: Add salt and vinegar (if using) to the mixture, stirring to combine.
11. Cool and Store: Allow the mixture to cool completely. Transfer the pickle to a clean, dry glass jar with a tight-fitting lid.
12. Mature the Pickle: Store the jar in a cool, dry place for at least a week to allow the flavors to meld and develop. Shake the jar occasionally to mix the contents.