When Purnima(full moon) occurs in the month of Ashwin then it is known as Sharad Purnima. It is said that on this day Lord Krishna performed Rasleela with Gopis in Nidhivan of Braj.
On Sharad Purnima idols of Lord Krishna are dressed with white clothes and beautiful jhankis are decorated.
Kheer is made on the occasion of Sharad Purnima. This kheer is kept under the moonlight for complete night. Then it is eaten as prasad in the morning. It is said that on the night of Sharad Purnima moon gives out amrit(अमृत) rays(किरणें), which makes the kheer rich with medicinal properties.