There is a believe that Lord GaneshaGanesha
The guardian deity of Hindus, also known as the Ganapati (The God of all groups) is the son of Lord Shiva ... can be easily pleased by offering Modakas & Druva Grass.
Druva grass can survive in dry condition as its roots go deep in search of water. When one Pluck a blade of grass and it sprouts back, and this attribute makes it a powerful symbol of regeneration, renewal, rebirth, fertility, and hence prosperity.
Modak: Sweet dumpling made of rice flour, stuffed with grated coconut and jaggery.
Once there was a demon named Anlasura. He created havoc in the heaven that even the gods were scared of him. God Indra tried many strategies to control him, but all went in vein. God Indra and other Gods decided to visit Lord Shiva’s abode to request Lord ShivaShiva
Shiva is one of the Supreme Gods of Hindu Trinity that ...
to help them to get rid of Anlasura. God Shiva pacified them and said that his son Ganesha would overthrow horrible demon Anlasura. Ganesha was an obedient child and thus immediately followed the instruction of his father and went along with the God to kill Anlasura .
God Ganesha stood in front of Anlasura and said that he came there for fighting with him. Anlasura laughed and started making fun of Ganesha that one small chubby child with elephant head came to kill him. God Ganesha smiled and began to grow and soon assumed his universal form and swallowed Analsura. Instantly after that God Ganesha's stomach began to burn. God Indra presented Moon to God Ganesha to be worn on his forehead, Lord Vishnu presented his Lotus, Lord Varuna showered plenty of water, Lord Shiva tied a thousand-headed serpent around belly but nothing could comfort Ganesha. Then a group of sages came, and they offered 21 blades of Dhruva grass to him. As soon as he ate them, the burning in his stomach subsided. Since then Dhruva grass is considered sacred and favorite of God Ganesha.
Legend related to Ganesha and Modaks:
Parvati praised about the scent of the divine Modak that can lead to the salvation. She further acclaimed that whoever would smell it, become the scholar of each and every subject and would be considered as Genius.
Both the brothers were impatiently waiting to get the Modak. However, Goddess Parvati was confused to whom to give that Modak. In order to settle the matter, she told her sons that whoever among them proved his superiority through sincere and honest actions would get that divine Modak.
On hearing their mother, on one hand Lord Kartikeya instantly decided to take the round of the world and cover all the pilgrimages in very short duration on his peacock. On the other hand, Lord Ganesha folded his hands and encircled around his parents three times. After completing his rounds, he stood there with folded hands before his parents and said that fasting, donating or visiting the places of pilgrimages is not even equal to one sixteenth of the devotion for one’s parents. This way he contented her mother Parvati and got the divine Modak. Goddess Parvati blessed him for the devotion he had for his parents. She also said that the any devotee who pray God Ganesha first and offer Modaks to him would definitely achieve his worldly as well as spiritual goals.
Since then devotees offer Modakas & Druva Grass to Ganesha to please him.