In a pressure cooker, add washed kachalu, water and salt. In 1 kg, we get 3 kachalu (2 big & 1 medium sized). This number may vary depending upon the size of each kachalu.
Pressure cook them for 5 to 6 whistles. Less cooking will leave them little raw from within & over boiling may turn them mushy. They must be as soft as properly boiled potatoes or boiled arbi.
Take them out of pressure cooker and let them turn completely cool. In the meantime, proceed to next step.
FOR MAKING TAMARIND PULP
Take tamarind in a bowl and add water in it. In winters, prefer to add bit warm water.
Mash it to take out the pulp out of it.
Strain the pulp in another bowl and keep aside.
ASSEMBLING OF KACHALU
By now, kachalu must have been turned cool. Remove their skin.
Cut them into a reasoned size pieces in a bowl.
Add tamarind pulp along with all other ingredients mentioned under the head "For Assembling Kachalu" in the list of ingredients. Remember, the carom seeds are added only after they were dry roasted on hot tawa till turned black.
Give a good mix to it. Taste & adjust the seasoning, if needed and your kachalu chaat is ready. Enjoy.
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Notes
1. If you like, you can also add boiled lobia/a black eyed pea or bean in it. Kachalu are sold both ways, with lobia (dry), without lobia.2. Here's one suggestion. Don't add all tamarind pulp and chilli (both red & green) in one go. Everyone in the family has different taste and acceptability to tanginess and spiciness. You can adjust these two later also after separating the share of those who want kachalu to be less tangy, less spicy.