Wash the gooseberries, keep aside. Soak tamarind in 1 1/2 cups of water, keep aside.
Boil 7 to 8 cups of water. Drop in the gooseberries and boil them for 8-10 minutes. Turn off the stove as soon as you see the gooseberries change colour.
Drain and pat dry. Dry in sunlight for an hour or two to remove the excess moisture. Meanwhile extract the juice of the soaked tamarind.
Heat a pan and pour in the tamarind pulp and bring it to a boil. Simmer and continue boiling it until it thickens. The consistency should be almost like cream.
Drop in the gooseberries, add salt and all the spice powders. Mix well. Simmer for another 3-4 minutes and turn off the stove.
Heat oil in a skillet and once hot, add in mustard and cumin seeds and allow them to splutter.
Add in the fenugreek seeds. Add turmeric and broken red chillies and then finally add asafoetida and turn off the stove.
Add this tempering into the prepared pickle when both pickle and tempering are hot. This helps absorbing all the flavours. Mix well.
Once cooled transfer it into an air tight container and store it in a dry place. It can even be refrigerated.