To Make the Karuveppilai Podi / Curry leaves powder -
Wash and dry the curry leaves well.
In a kadai / pan, heat 1 tsp of oil in low flame. Add the curry leaves and mix well. Keep stirring to evenly roast the leaves. Make sure to do this in low heat. The curry leaves should not change color. It should just fry and become crispy. It will take a good 6 to 7 minutes on low flame. You will notice that the leaves start to become crunchy.
Remove the fried curry leaves in a bowl.
In the same pan, heat one more tsp of oil and fry the Urad dal, Chana dal, Coriander seeds, Red chilies and black pepper. Fry until they are aromatic. Add the Asafetida, salt and tamarind piece at the end and fry for a minute. Turn off the the heat and then add the fried curry leaves to the pan and let the whole mixture cool down to room temperature.
Grind the mixture to a smooth powder. You can make it very smooth or leave it a little chunky based on your preference. The karuveppilai powder is now ready. This powder can be stored for a later use as well.
To make the Karuveppilai Sadam -
Cook the rice and let it cool down. I usually add a little oil to keep the rice from sticking.
In a wide pan, heat 1 TBSP of gingelly oil and add the mustard seeds. Let the seeds crackle and then add cashews. You could also use peanuts instead of cashews for a different taste.
Once the nuts are fried, add the cooked and cooled rice along with the ground curry leaves powder. I used 3/4 of the powder that I ground. Add half of the powder and gently mix to combine. Taste and adjust the salt if needed. If needed, add more karuveppilai powder and mix.