Set a cast-iron wok on high heat. Pour in the coconut oil. Tip in the chilies and stir for a minute.
Lift out the chilies with a perforated ladle and set aside.
Put the shallots into the wok and stir continuously for 5 minutes.
Switch off the heat. Lift out the shallots and put them aside along with the chilies.
Keep the remaining oil in the wok itself to use later.
Put the tamarind into a small pan. Pour in 250 ml of water and put on the stove.
As soon as it boils, switch off the heat. When cool, squeeze and sieve the tamarind juice. Discard the fibers and set the juice aside.
Break the fried chilies each into 2 or 3 pieces.
Put the broken chilies and the shallots into a mortar. Use the pestle to crush them into a coarse paste. If mortar and pestle are not available, just put them into your food processor and grind for 10 seconds.
To cook:
Set the cast-iron wok containing the oil back on high heat. Tip in the mustard seeds.
As soon as the mustard seeds are about to finish popping, pull the curry leaves off their sprigs and tip them in.
Stir once and tip in the shallot-chili paste. Stir continuously for 2 minutes.
Pour in the tamarind juice and tip in the salt. Pour in the remaining water (750 ml).
Once it comes to a boil, let cook for a minute and then switch off the heat.
Your delicious shallot rasam / mulaku varutha puli / cheriyulli rasam is ready to serve. Serve with a pile of steaming hot rice or with upma and enjoy!