Soak a lemon sized tamarind ball in 1 & 1/4 cup hot water for atleast 15 minutes and keep aside.
Wash, peel and finely chop ginger as shown below. Note - Use ginger peel / skin when making tea.
Wash, pat dry and roughly chop the green chilies
Squeeze the soaked tamarind and extract pulp.
Now add 1 cup of warm water to the tamarind, repeat the squeezing process to collect some more tangy liquid extract. Strain this and keep aside.
Now heat a pan or wok, add oil.
Add mustard seeds to the hot oil and once it crackles, add whole red chilies and some hing.
Now add finely chopped ginger or adrak and sauté on low heat until the ginger slightly softens (say 3 to 5 minutes).
Add the green chilies and sauté well for another 2 to 3 minutes.
To the ginger and green chilies mixture, add the strained tamarind pulp.
Add a tsp of turmeric powder and red chili powder and stir everything well. Add salt to taste.
Now let this simmer on low heat until the raw tamarind smell vanishes and the liquid volume slightly reduces. This takes about 10 to 15 minutes on low flame. PS - Keep stirring this every now and then.
Once the raw smell of tamarind is gone, add jaggery and mix.
The pickle will slowly start to thicken with the jaggery melting.
Check seasoning, add extra if required. If the mixture is too tangy, add extra jaggery.
Keep stirring puli inji until it thickens and forms a dark caramel texture.
Switch off the heat, allow puli inji to cool before transferring to a clean, dry and airtight glass jar.