Directions

1. Place sesame seeds in a saucepan. Using medium heat, toast sesame seeds stirring occasionally for about 5 minutes or until the seeds are fragrant and start to have a few popping sounds. Allow it to cool completely to room temperature.
   
2. Transfer the cooled sesame seeds into a processor or a container of a hand held processor. Add water and process into a smooth paste as much as possible. You may add more water to process mixture into smoother texture but adding more water means that you will need a longer time to cook it off later. For a smoother texture, ground processed mixture in batches into smoother paste using a mortar and pestle and transfer the ground paste into a clean saucepan.
   
3. Transfer sesame mixture into a small pan and add oil. Cook on medium heat, stirring until mixture is pasty and fragrant, then add sugar. You will notice that the mixture will become wet and darker after the addition of sugar.
   
4. Continue to cook on medium heat, stirring constantly until the liquid has dried up and you have formed a firm paste. Cool and use as filling for steamed buns. Freeze filling prior to using for buns.