- Add water, rock sugar, and the cleaned, tied pandan leaves into a large pot.
- Bring to a boil until the sugar is completely dissolved, then reduce to low heat and simmer for another 15–20 minutes to let the pandan aroma infuse.
- Turn off the heat and remove the pandan leaves.
- Let the syrup cool completely, then slowly add pomelo blossom essential oil while stirring and tasting until the desired fragrance is achieved.
- Note: Do not add the essential oil while the syrup is still hot to prevent the aroma from evaporating.
- Store the syrup in the refrigerator.