There is a Hindu festival called "Tulsi Bibaha". It was held yesterday according to the Hindu calendar. Ancient story tells that Goddess Tulsi was married to Lord Vishnu on this day. So on the same day, Tulsi(Holy Basil Plant) is married to a black stone that is called Shaligram. It is told that Lord Vishnu, known as the protector of the Universe, married Tulsi taking the form of Shaligram. People usually take fast during this day. And then prepare sweet dish in their home. In our Nepali culture, there is the tradition of eating boiled sweet potatoes and cocoyam. After performing this ritual, the wedding done after this day is considered to be very auspicious. Now its a season of wedding ceremony in Nepal. Many people get married in this month of Mangsir.
My mom also bought some sweet potatoes and cocoyam from the market. I just washed off the dirt and unnecessary roots from these and left it to be boiled in rice cooker for about half and hour. In India, Hindu people have the tradition of making pudding(kheer) from the same. I don't know what's the connection of consuming such food during this ceremony.