In a bowl, add glutinous rice bowl, corn starch, sugar, and water. Mix well until no clumps.
Add vegetable oil and mix well.
Add food coloring and mix well. You can adjust to your preferred color by adding more drops. Please note that the mixture color will darken after steaming.
Steam the mixture with high heat for 15-20 minutes. The rice cake is fully cooked when there is no liquid coming out when you poke it with a fork.
Remove the bowl from the heat. Set it aside to cool down a bit. If you would like to fasten the process, put it in the freezer for 5 minutes or until lukewarm.
Once cool down, knead the rice cake for 5-10 minutes or until the dough is smooth and stretchy. Please remember NOT to use bare hands and wear gloves instead, because it is very sticky.
Wrap the rice cake with plastic wrap. Put it in the fridge for 10 minutes.