Take a heavy-bottomed saucepan. Add water, granulated sugar and brown sugar in it.
Heat it over a medium flame/heat. Bring it to a boil.
Then reduce heat and let it simmer for 8-10 minutes or until the syrup thickens a little (The syrup thickens significantly as it cools, so don’t cook it for too long).
Turn the heat off and pour vanilla essence. Mix well.
Allow it to cool down to room temperature. Then pour it into a glass jar or bottle.
Place it in the refrigerator and you can use it for up to 2 weeks.