Just as with Karthigai, there are several stories that surround Thiruvadirai, also known as Thiruvadhira or Arudhra Darisanam. The day is celebrated with great fervour at the famous Chidambaram temple dedicated to Lord Nataraja. It's celebrated on the Purnima thithi in the Tamil month of Margazhi, which is also said to be the longest night of the year.
         Most south indian households prepare Kali-Kuzhambu (the 'L' in the Kali is stressed and not like the 'L' in Goddess Kali). Now this is a unique combination, because Kali is sweet and the kuzhambu or stew is pretty much like Sambhar, while some make it in a different style.
Here's the recipe for the Kali, quite simple but very delicious.

THIRUVATHIRAI KALIIngredients : Rice - 1 cup
Channa dal (Bengal gram) - 2 tbsps
Moong dal (Green gram) - 1 tbsp
Grated Jaggery - 1 3/4th cups
Cardamom powder - 1 tsp
Ghee (Clarified butter) - 2 tbsps
Cashews - a handful

Method :
1. Dry roast the rice over low heat till it turns light brown. Keep aside.
2. In the same wok, dry roast the lentils till they let out a roasted aroma. Take care not to let them turn dark. Keep aside and let cool.
3. Now dry grind the rice and lentils together to a coarse, semolina (rava) like consistency.
4. Add the jaggery to the wok, along with 1.5 to 2 cups water.  Let simmer on low-medium heat till jaggery dissolves. We dont need a thick syrup consistency here.
5. Now add the rice-lentils ...