In Hindu religion, Dwadasi Parayanam is considered to be the best. A quote below a verse that supports this:
Na Annodhakath Param Dhanam
Na Dwadhashyat Param Vratam
Na Gayathrayat Param Mantram
Na Maata Para Devatha
There can be no better charity than providing food and water,
There is no vratham that is superior to Dwadasi
There is no Mantra that is superior to Gayathri and
There is no God superior to one's own mother. (Source ramanuja.org)
Ekadasi vratham is observing total fast (suddha upavasam) on Ekadasi tithi. Timely breaking of the fast on Dwadasi is as important as observing the fast on Ekadasi. Normally, the fast must be broken before trayOdasi arrives. If there is insufficient time, the fasting can be broken with Tulasi water.
People fast on ‘Ekadasi’ day and have ‘Dwadasi Paranai’ (special food or thali) on the next day which levels the acidity and the menu by itself is fantastically medicated. We don’t use tamarind for this thaligai (samayal).
Concerning the food for Dwadasi pAranE, one should avoid using anything related to plantains (vazhai kaay, ilai etc.), also avoid tamarind. One can substitute lemon or dry mango Powder for tamarind
Dwadasi Thaligai Menus are:(Please click the links)