Sharad Purnima also known as Rass Purnima is dedicated to Goddess Lakshmi. On this day, devotees take a holy dip in the river and pray for happiness and prosperity. On this day, devotees fast, take the holy dip, and also prepare rice kheer using Ganga Jal and keep it under the moonlight and then the next day, the kheer is consumed as bhog.
Why is kheer made on this day and kept under full moon?
As per Hindu religion, Sharad Purnima marks the beginning of the winter months, and on this day, Chandra Dev (moon) is worshipped. As a tradition, people make rice kheer on the night of Sharad Purnima and keep it under the open sky in silverware, and consume it the next morning. It is believed that the winter dew brings down the lactic content of milk and the bright light of the moon reduces the starch level of rice, and when served in silverware, the kheer helps boost the immune system. Also, it is believed that the rays of the moon have certain healing properties that nourish the human body.
It is also believed that on this day, Maa Lakshmi comes to roam around the earth, and those who invoke her at night on Sharad Purnima by offering kheer to the moon receive the grace of the deity.